Patent Description:
In an environment in which an apparatus operates, there is a possibility that a human body is damaged by the apparatus in a state in which the human body can freely come into contact with the operating apparatus. In the environment in which the apparatus operates, an operation region in which the apparatus operates is comparted by a protective fence or a compartment panel in order to prevent the human body from being damaged by the operating apparatus, in other words, in order to realize a safe state. One method for realizing the safe state by comparting the operation region is a method in which an operation region is comparted by, a fixed portion such as a protective fence, to prevent a human body from entering the operation region, that is, the operation region is isolated from a region where the human body is present. Another method is a method of constructing a compartment system capable of comparting an operation region and limiting operation of an apparatus. In the compartment system, a compartment in which an operation region is comparted by a fixed portion, such as a protective fence, and then, an opening in a part of the compartment and a movable portion that opens and closes the opening are installed, that is, a compartment allowing a worker to enter the operation region is formed. In this compartment system, a control system is constructed so as to monitor the movable portion and control the apparatus operating in the operation region not to damage the human body in accordance with the monitoring result. In such a compartment system, a safety switch that monitors opening and closing of the movable portion is installed in a region of the opening where the movable portion is installed.

The safety switch includes a switch body arranged at the fixed portion of the compartment, and an actuator arranged on an openable and closable door constituting the movable portion of the compartment. The safety switch detects and outputs opening of the door, which is the movable portion, as a function for maintaining the operation region in a safe state, and the apparatus in the operation region is controlled to a state in which the human body is not damaged in response to the output from the safety switch in the entire compartment system. For example, a safety measure for an environment in which the apparatus operates is taken by adopting a system configuration in which the apparatus in the operation region is stopped in response to the output from the safety switch.

As one type of safety switch, a safety switch with a lock pin mechanism is disclosed in <CIT>. The safety switch with a lock pin mechanism includes an actuator bolt installed in a compartment fixed portion and a switch body installed in a door, and the switch body is provided with a lock pin. The actuator bolt and the switch body are arranged at relative positions facing each other when the door is closed. In the lock pin mechanism, a locked state in which the actuator bolt and the lock pin are physically integrated is formed by mechanically engaging the lock pin with the actuator bolt. The safety switch with a lock pin mechanism is provided with a detection mechanism so as to be capable of detecting that the locked state of the safety switch with a lock pin mechanism, and performs output to indicate a state not being the locked state at least when the locked state is not formed. When the door is closed, and then the lock pin mechanism is brought into the locked state, the openable and closable door in the closed state is fixed in a state of being integrated with the compartment fixed portion. Conversely, an unlocked state is formed when the lock pin is removed from the actuator bolt, and the door can be opened.

<CIT> discloses a safety switch with an electromagnetic lock mechanism, which is another type of safety switch. That is, the safety switch with an electromagnetic lock mechanism includes an electromagnet and an actuator magnetized member that is attracted to the electromagnet. The actuator magnetized member is installed in a door constituting a movable portion, and a switch body including an electromagnet is installed in a compartment fixed portion such as a protective fence. The electromagnet is driven such that the actuator magnetized member is attracted to the electromagnet, thereby forming a door-locked state. The safety switch includes a display unit. The display unit displays a safe state of an operation region.

<CIT> also discloses a module including a monitoring sensor and a monitoring actuator for monitoring opening and closing of the door. The monitoring actuator is installed in the openable and closable door, and the monitoring sensor is installed in the compartment fixed portion. When the monitoring actuator moves away from or approaches the monitoring sensor in accordance with opening and closing of the door, which is the movable portion, the monitoring sensor generates a door signal including a first state signal indicating "the door has been opened" or a second state signal indicating "the door has been closed".

In a safety switch including a door lock mechanism, a function for safely maintaining an operation region is to monitor opening and closing of an openable and closable door and output a result of the monitoring to a control apparatus capable of controlling an apparatus operating in the operation region, and a door lock function contributes to maintaining a closed state the openable and closable door.

As a characteristic of the safety switch including the electromagnetic lock mechanism as the door lock mechanism, a state in which an attracting surface of the electromagnet and a surface to be attracted of the actuator are in close contact with each other is required in order to exhibit a sufficient attracting force for maintaining the closed state of the openable and closable door. In other words, if there is a gap between the attracting surface and the surface to be attracted, it is difficult to exhibit the attracting force as designed. Thus, the attracting force as designed is sometimes not exhibited in a case where the attracting surface and the surface to be attracted do not come into close contact with each other even in the closed state of the openable and closable door, for example, in a case where a moving range of the openable and closable door is limited due to a door stopper of the openable and closable door or displacement of the openable and closable door after attachment of the safety switch so that the surface to be attracted of the actuator arranged on the openable and closable door does not come into contact with the attracting surface.

Regarding a configuration for bringing an attracting surface and a surface to be attracted into close contact with each other, in <CIT>, a socket that is stretchably deformable between a connection element and a base element in a configuration in which an iron piece (counterelement) is fixed to the base element via the connection element. The iron piece collides with an electromagnet with an operation in which a door closes. At this time, the iron piece is pushed in as the socket is deformed, and thus, an impact when the iron piece collides with the electromagnet is absorbed by the socket. According to such a configuration, a safety switch can be arranged in such a positional relationship that the electromagnet and the actuator collide with each other when the door is closed in order to bring the attracting surface and the surface to be attracted into close contact with each other.

That is, <CIT> discloses a configuration in which the surface to be attracted moves in a direction of being pushed in as the configuration for bringing the attracting surface and the surface to be attracted into close contact with each other.

As described above, it is difficult to exhibit the electromagnetic force as designed even if a slight gap with an extent of, for example, about one piece of paper, partially exists between the attracting surface and the surface to be attracted when the door is closed. Thus, for example, the safety switch is used to stop rotation of the door to be closed such that the attracting surface and the surface to be attracted reliably come into contact with each other when the door is closed. Therefore, an impact due to a collision of the door that rotates to a closed state is applied to the safety switch although a part of the impact is absorbed by a deformable element, and thus, a strong and relatively large housing that can withstand the impact is required. <CIT> discloses safety switches according to the preamble of claim <NUM>. <CIT> discloses a shear-type electromagnetic lock whose armature can approach the electromagnet from any transverse direction, which can be mounted in any orientation with respect to gravity, and which does not require any door position sensing means. The armature includes a pair of standoffs in the form of conically projecting buttons affixed thereto, the buttons projecting from the plane of contact between the armature and the electromagnet. The armature is mounted to a sub-plate via counteracting springs such that the armature "floats" on the sub-plate, with the distance between the armature and the sub-plate being adjustable via adjusting screws. A matching electromagnet assembly for mounting to a door frame includes matching conical depressions positionally corresponding to the conical buttons such that the buttons seat into the depressions when the armature and electromagnet are properly aligned. <CIT> discloses an electromagnetic door lock assembly that employs an electromagnet positioned in a frame adjacent to a door and an adjustable armature assembly positioned in a door for interaction with the electromagnet. The armature assembly includes an armature plate having a front surface and a back surface opposite from the front surface, a backing plate situated adjacent to the back surface of the armature plate, and a stem coupling the backing plate to the armature plate including a spring biasing the backing plate and armature plate toward each other. The armature plate moves between a first position for interaction with the electromagnet and a position contiguous to the electromagnet. Technological background is disclosed in <CIT>.

An object of the invention is to provide a small safety switch with an electromagnetic lock mechanism that can establish close contact between a surface to be attracted and an attracting surface at a high level when an openable and closable door is closed and form a state in which the surface to be attracted and the attracting surface overlap each other without a gap.

In view of the above technical problem, the invention provides a safety switch according to independent claim <NUM>, and a safety switch according to independent claim <NUM>.

According to the invention, the actuator is offset toward the switch body side in a process of closing an openable and closable door. Thus, if the openable and closable door is movable to a position where the surface to be attracted can come into contact with the surface to be attracted by the offset of the actuator, a close contact state between the attracting surface and the surface to be attracted is formed by the movement mechanism. As a result, the close contact state between the surface to be attracted and the attracting surface can be established at a high level.

Operational effects and other objects of the invention will be apparent from the following detailed description of preferred aspects for carrying out the invention.

Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. <FIG> is an explanatory view of an openable and closable door and a protective fence in which a safety switch of an embodiment, that is, a safety switch with an electromagnetic lock mechanism is installed as a compartment system <NUM>. <FIG> is a cross-sectional view taken along line II-II in <FIG>. In the drawings, reference sign PF denotes the protective fence, and reference sign PD denotes the openable and closable door. <FIG> is an explanatory view when the compartment system <NUM> is seen from outside an operation region S comparted by the compartment system <NUM>. The compartment system <NUM> includes: the protective fence PF as a compartment fixed portion; the door PD constituting a movable portion movable relative to the compartment fixed portion; and a safety switch <NUM>.

The compartment system <NUM> maintains the operation region S in a safe state by limiting operation of an apparatus inside the operation region S based on a safety-related output that is output from the safety switch <NUM>. In the present embodiment, the safety switch <NUM> is arranged in the operation region S. The protective fence PF constitutes the compartment fixed portion of the compartment system <NUM> that comparts the operation region S in which the apparatus operates. An opening at which the door PD constituting the movable portion is installed with respect to the compartment fixed portion is formed by a door opening frame <NUM>. Referring to <FIG>, a plurality of hinges <NUM> separated up and down are provided on one side of the door PD constituting the movable portion, and the door PD is attached to a vertical frame portion 2a of the door opening frame <NUM> via the plurality of hinges <NUM>. That is, the door PD is a single-swing door.

Referring to <FIG> and <FIG>, the door PD includes a door frame <NUM> and a transparent board <NUM> surrounded by the door frame <NUM>. The door PD has the hinges <NUM> attached to one side thereof and a door operating portion <NUM> attached to the other side thereof (<FIG>). When the door operating portion <NUM> is operated, a door latch (not illustrated) disengaged from the door opening frame <NUM> is opened, and the door PD can be opened.

<FIG> illustrates a state in which the door PD is closed, and the door frame <NUM> constituting the door PD is in contact with a door stopper <NUM> and is positioned. In <FIG>, the operation region S comparted by the protective fence PF and the openable and closable door PD is a region located on the right side of the protective fence PF and the door PD on the paper surface of <FIG>. The safety switch <NUM> is arranged on the operation region S side in relation to the door PD in the closed state. The safety switch <NUM> is arranged so as to be located on the operation region S side with respect to the door PD in the closed state of the door PD, whereby the safety switch <NUM> is arranged inside the operation region S. Referring to <FIG>, the safety switch <NUM> includes a switch body <NUM> and an actuator <NUM>. The switch body <NUM> is arranged inside the operation region S. Specifically, the switch body <NUM> is fixed to a surface of an upper side horizontal frame portion 2b of the door opening frame <NUM> on the operation region S side via a first bracket <NUM>. The switch body <NUM> includes an electromagnet <NUM> having an attracting surface 130a. In the closed state of the door PD, the switch body <NUM> is installed in the door opening frame such that the attracting surface 130a faces the door PD, in other words, faces the outside of the operation region S. Note that arrows X, Y, and Z indicating three directions orthogonal to each other are illustrated in <FIG>, but are associated with arrangement attitudes of the safety switch <NUM> as will be described later.

As will be described later with reference to <FIG> and the like, the switch body <NUM> of the safety switch <NUM> of the embodiment includes the electromagnet <NUM> (<FIG>) and a board accommodating portion <NUM>, and boards Cb(<NUM>) and Cb(<NUM>) (<FIG> and <FIG>) are accommodated in the board accommodating portion <NUM>.

On the other hand, the actuator <NUM> is arranged on a surface of the door frame <NUM> on the operation region S side, and specifically, is fixed to an upper side frame portion 6a of the door frame <NUM> via a second bracket <NUM> (<FIG>). The door opening frame <NUM> and the door frame <NUM> both have a closed rectangular cross section which is a known structure, but may have a U-shaped cross section or an L-shaped cross section as a modification.

The door PD is related to an openable and closable door described in <CIT>. On the other hand, <FIG> illustrates box-shaped apparatuses <NUM> each accommodating a work system. In <FIG>, three apparatuses <NUM> are arranged side by side. A double-hinged openable and closable door <NUM> as an example of the door PD is attached to a box <NUM> of each of the apparatuses <NUM> such that a worker can manually access an apparatus <NUM> installed therein. Regarding the openable and closable door <NUM>, the safety switch <NUM> can be installed in the box-shaped apparatus <NUM>.

Hereinafter, as a typical example, an embodiment of the invention will be described based on the embodiment applied to the door PD disclosed in <FIG> and <FIG>. <FIG> is a substantial front view of the actuator <NUM> included in the safety switch <NUM>, and is a view for describing a front shape of the actuator <NUM>. The actuator <NUM> includes an iron piece <NUM>, which is a member to be magnetized, as the main part, and includes a plastic molding <NUM>, an actuator communication unit <NUM>, and an attachment fitting <NUM> which is an actuator attachment portion. The iron piece <NUM> has a circular shape in a front view, and has a surface to be attracted 120a, which is attracted to the attracting surface 130a, on a front surface. A diameter of the iron piece <NUM> is indicated by reference sign D1. The iron piece <NUM> is attached to the plastic molding <NUM>. The periphery of the iron piece <NUM> is covered with the plastic molding <NUM>, and the actuator communication unit <NUM> is arranged in a mode of being covered with the plastic molding <NUM>. The attachment fitting <NUM> is provided on a side opposite to the iron piece <NUM> with respect to the plastic molding <NUM>, and has a shape extending to the left and right on the paper surface of <FIG>. In the attachment fitting <NUM>, a pair of attachment holes through which screws for fastening the attachment fitting are inserted is provided in a portion viewed from the front of the actuator <NUM>. A pair of the attachment fittings <NUM> is fastened to the second bracket <NUM>, and the actuator <NUM> is fixed to the door PD via the second bracket <NUM> (<FIG>). In the closed state of the door PD, the actuator <NUM> and the switch body <NUM> have a relative positional relationship in which the actuator <NUM> is located on the surface of the door frame <NUM> on the operation region S side. That is, the actuator <NUM> is installed on the door frame <NUM> such that the surface to be attracted 120a of the iron piece <NUM> is oriented to the operation region S in the closed state of the door PD. On the other hand, the switch body <NUM> is located inside the operation region S. Note that the actuator <NUM> is fixed to the door PD via the second bracket <NUM> in the present embodiment, but it may be configured such that the attachment fitting <NUM> is directly fastened to the door frame <NUM> to fix the actuator <NUM> to the door PD.

An arrangement example when the actuator <NUM> is fixed to the door PD will be specifically described based on an arrangement example illustrated in <FIG>. As described above, the actuator <NUM> is fixed to the upper side frame portion 6a of the door frame <NUM>. In the present embodiment, the attachment fittings <NUM> are fixed such that the attachment holes of the pair of attachment fittings <NUM> of the actuator <NUM> are arranged side by side in the lateral direction, that is, in the longitudinal direction of the upper side frame portion 6a. In this installation example, reference sign Ha in <FIG> indicates q height of the iron piece <NUM> included in the actuator <NUM> and having a circular shape in the front view. In the installation example of <FIG>, the actuator <NUM> is fixed to the door frame <NUM> in a state in which a direction of the height Ha is aligned with a direction of a width Wdf of the upper side frame portion 6a. The height Ha of the actuator <NUM> is equal to or smaller than the average width Wdf of the door frame <NUM> having a rectangular cross section (<FIG>). A part of the actuator <NUM> installed on the door frame <NUM> may protrude to the inner side of the door frame <NUM>, that is, to a site of the transparent board <NUM>, but a protruding amount thereof is desirably as small as possible. As a result, it is possible to reduce the presence of the actuator <NUM> from hindering work.

In the safety switch <NUM> of the present embodiment, the electromagnet <NUM> of the switch body <NUM> and the iron piece <NUM> of the actuator <NUM> function as an electromagnetic lock mechanism. Then, the electromagnetic lock mechanism of the safety switch has been historically developed following a technical idea of a lock pin mechanism as described above. A design concept of a safety switch <NUM> with the electromagnetic lock mechanism of the embodiment will be described. In general, when a role of the safety switch is examined, an original request to maintain an operation region in a safe environment in the operation region in which an operating apparatus is arranged is realized by a function of detecting opening and closing of a door, and a role required for a door lock function is to allow the apparatus to continuously operate in the operation region. Therefore, it can be said that it is sufficient that the door lock function can realize continuous operation of the apparatus in the operation region. In other words, a basic requirement of the door lock function of the safety switch is to prevent inadvertent opening of the openable and closable door during the operation of the apparatus. This is because the operation of the apparatus is limited in the operation region by the function of the safety switch for maintaining the operation region in the safe environment when the openable and closable door is inadvertently opened. That is, it can be said that the essential role of the door lock function required for the safety switch is to prevent the operation of the apparatus in the operation region S (<FIG>) or the box <NUM> (<FIG>) from being interrupted by the inadvertent opening of the door PD or <NUM>.

Conventionally, a door lock function of a safety switch has been designed to contribute to maintaining an operation region in a safe environment. Thus, an electromagnet having a strong magnetic force to such an extent that the door is not opened even with a relatively strong operation force has been also adopted for an electromagnetic lock mechanism. However, from a viewpoint of considering the role of the door lock function as allowing the apparatus to continuously operate instead of maintaining the safe environment, the degree of a magnetic force of the electromagnet adopted in the safety switch with an electromagnetic lock mechanism may be the same as or weaker than the conventional case. When the worker performs an operation of opening the door PD, it is possible to prevent the inadvertent opening of the openable and closable door by obtaining an operation force with which the worker can be asked of at least "Are you now performing an operation of opening the door PD according to your will?" regarding the operation force required to open the door PD. In order to open the door PD, if a certain operation force capable of confirming the will of the worker is obtained by the electromagnet, it is possible to prevent the inadvertent opening of the door PD without obtaining any more operation force.

Therefore, optionally, in a case where the degree of the magnetic force of the electromagnet <NUM> is set to be weaker than the conventional case, for example, in a case where the door PD includes an operating portion such as a door knob, a door latch is released when an operation force for rotating the door knob is applied to the door knob, and at least the electromagnet <NUM> having a magnetic force stronger than the operation force for releasing the door latch is used. This makes it possible to discourage the worker from opening the door PD, and to prevent the inadvertent opening of the door PD. Then, it is possible to avoid unexpected interruption of the operation of the apparatus caused by the inadvertent opening of the doors PD and <NUM>.

Referring to <FIG>, the switch body <NUM> has a screw hole 130c as an attachment portion for fixing the switch body <NUM> to the door opening frame <NUM> which is a fixed portion of the compartment system <NUM>.

More specifically, the electromagnet <NUM> has a protrusion 130b protruding along a direction from the center of the attracting surface 130a toward the outside, and the screw hole 130c is provided in the protrusion 130b. When description is given with reference to the arrangement example illustrated in <FIG>, the switch body <NUM> is fixed to the upper side horizontal frame portion 2b of the door opening frame <NUM> via the first bracket <NUM> having an L-shaped cross section (<FIG>). When description is given with reference to the arrangement example of <FIG>, the protrusion 130b is located so as to protrude from an upper portion of the electromagnet <NUM>, a flat top surface of the protrusion 130b constitutes an attachment surface, and the screw hole 130c is provided in the attachment surface. This attachment surface may be formed on a side surface of the electromagnet <NUM>.

For example, <FIG> illustrates the arrows X, Y, and Z indicating three directions orthogonal to each other.

Directions indicated by the arrows X, Y, and Z all correspond to arrangement attitudes of the safety switch <NUM>, and the directions indicated by the arrows X, Y, and Z are referred to as an X-axis direction, a Y-axis direction, and a Z-axis direction, respectively. The Y-axis direction indicates a normal direction of the attracting surface 130a of the electromagnet <NUM>. The Z-axis direction indicates a direction which is orthogonal to the Y-axis direction and parallel to the attracting surface 130a, and in which the protrusion 130b protrudes with respect to the center of the attracting surface 130a. The X-axis direction indicates a direction parallel to the attracting surface 130a and orthogonal to the Z axis. As illustrated in <FIG>, since the safety switch <NUM> of the present embodiment is arranged such that the attracting surface 130a faces the door PD in the closed state, a normal direction of the door PD in the closed state coincides with the Y-axis direction. Further, the safety switch <NUM> of the present embodiment is arranged such that a direction in which the protrusion 130b protrudes with respect to the center of the attracting surface 130a is orthogonal to an extending direction of the upper side frame portion 6a of the door PD in the closed state and an extending direction of the upper side horizontal frame portion 2b of the door opening frame <NUM>. Thus, in the present embodiment, the extending direction of the upper side frame portion 6a and the extending direction of the upper side horizontal frame portion 2b coincide with the X-axis direction, and a direction toward the operation region S with respect to the door PD, that is, a depth direction of the operation region S coincides with the Y-axis direction. Note that, in the following description, a direction from the door PD in the closed state toward the attracting surface 130a in a Y-axis direction and an opposite direction thereof are sometimes referred to as "rear or rearward" and "front or forward", respectively, and a direction from the attracting surface 130a toward the protrusion 130b in a Z-axis direction and an opposite direction thereof are sometimes referred to as "above, upper side, or upward" and "below, lower side, or downward", respectively.

<FIG> are views related to the switch body <NUM>. <FIG> is a perspective view of the switch body <NUM>. <FIG> is a front view. <FIG> is a side view. As can be clearly seen from <FIG> and <FIG>, the switch body <NUM> has a substantially cylindrical overall shape extending in the Y-axis direction (normal direction of the attracting surface 130a). The switch body <NUM> includes the electromagnet <NUM> including the attracting surface 130a constituting one end surface in the Y-axis direction. A length L from the attracting surface 130a to the other end surface is longer than a diameter of the attracting surface 130a.

The attracting surface 130a forms the main part of the one end surface of the switch body <NUM>. More specifically, referring to <FIG>, reference sign Hg in the drawings denotes a housing of the board accommodating portion <NUM>. In a case where the housing Hg is provided in the periphery of the electromagnet <NUM>, the attracting surface 130a protrudes from an end surface Hg(a), which is a part of the housing Hg and extends to the electromagnet <NUM>, and the attracting surface 130a forms the one end surface of the switch body <NUM>. As described above, the attracting surface 130a faces the surface to be attracted 120a of the actuator <NUM> when the door PD is closed.

As illustrated in <FIG>, the switch body <NUM> includes the housing Hg including the board accommodating portion <NUM> that accommodates the boards, and a display unit <NUM> that performs display corresponding to the safety-related output that is output from the safety switch <NUM> based on a detection result of the actuator <NUM>. The board accommodating portion <NUM> is located on a side opposite to the attracting surface 130a of the electromagnet <NUM> in the Y-axis direction. In other words, the board accommodating portion <NUM> is located at the rear of the electromagnet <NUM>. Thus, a dimension in the X-axis direction and a dimension in the Z-axis direction of the entire switch body <NUM> are less likely to be larger than a dimension in the X-axis direction and a dimension in the Z-axis direction of the electromagnet <NUM>. Further, the display unit <NUM> is located in the housing Hg on the side opposite to the attracting surface 130a with respect to the electromagnet <NUM> in the Y-axis direction, that is, at the rear of the electromagnet <NUM>. The switch body <NUM> has a shape in which a dimension in the Y-axis direction is larger than both the dimension in the X-axis direction and the dimension in the Z-axis direction. Thus, an area occupied by the opening formed in the door opening frame <NUM> is likely to be smaller when viewed from the front as compared with other switch bodies that require the same capacity.

<FIG> is the front view of the switch body <NUM> as viewed from the front. A normal direction of the paper surface of <FIG> is parallel to the Y-axis direction. As described above, the board accommodating portion <NUM> is located at the rear of the electromagnet <NUM>. Thus, when the switch body <NUM> is viewed from the front, most of the housing Hg including the board accommodating portion <NUM> is hidden by the electromagnet <NUM> as illustrated in <FIG>. Therefore, it is possible to suppress an increase amount of an area occupied by the switch body <NUM> when viewed from the front caused by providing the housing Hg. In the present embodiment, a ratio of an area occupied by the housing Hg to an area occupied by the attracting surface 130a is small when viewed from the front.

As illustrated in <FIG>, in a region occupied by the housing Hg when viewed from the front, a region located on a side where the screw hole 130c is provided with respect to the center of the attracting surface 130a is larger than a region located on a side opposite to the side where the screw hole 130c is provided with respect to the center of the attracting surface 130a. In other words, most of the housing Hg is located above the center of the attracting surface 130a in the front view. When the switch body <NUM> is fixed by screw hole 130c, a dead space is generated between a portion of the attracting surface 130a having a maximum dimension in the X-axis direction and the door opening frame <NUM> to which the switch body <NUM> is attached. When the dead space is utilized as the region where the housing Hg is provided, workability through the door opening frame <NUM> is less likely to deteriorate. Therefore, the housing Hg is configured such that an area occupied by the housing Hg in the front view is larger on the side where the screw hole 130c is provided with respect to the center of the attracting surface 130a, whereby the workability of work through the door opening frame <NUM> in which the switch body <NUM> is arranged is secured.

<FIG> is the side view of the switch body <NUM>. The switch body <NUM> has the board accommodating portion <NUM> on the side opposite to the attracting surface 130a with respect to the electromagnet <NUM> (<FIG>). Reference sign Hg denotes the housing of the board accommodating portion <NUM>. In the board accommodating portion <NUM>, a connector coupling portion <NUM> is provided on an end surface <NUM> on the side opposite to a side where the attracting surface 130a is located in the Y-axis direction, that is, on the rear side (<FIG> and <FIG>). The end surface <NUM> on the rear side is also an end surface of the switch body <NUM> on the side opposite to the side where the attracting surface 130a is located. The connector coupling portion <NUM> extends in a direction away from the attracting surface 130a along the Y-axis direction. Since the connector coupling portion <NUM> is provided on the end surface <NUM> of the board accommodating portion <NUM>, it is unnecessary to position a cable around the switch body <NUM> regarding the arrangement of the cable connected to the connector coupling portion <NUM>. Further, since the connector coupling portion <NUM> is provided on the end surface <NUM> of the board accommodating portion <NUM>, at least a portion of the cable connected to the connector coupling portion <NUM> in the vicinity of the connector coupling portion <NUM> is located at the rear of the switch body <NUM>. Thus, the cable reduces the possibility that the visibility of the display unit <NUM> from the front deteriorates. Further, when the cable connected to the connector coupling portion <NUM> is routed at the rear of the switch body <NUM> or routed above at a site where the screw hole 130c is located, the cable can be routed without being located in the vicinity of the opening formed by the door opening frame <NUM>, so that workability of work through the door opening frame <NUM> is less likely to deteriorate.

<FIG> is a longitudinal cross-sectional view of the switch body <NUM> taken along the Z-axis direction. <FIG> is a view for describing the arrangement of the two boards Cb(<NUM>) and Cb(<NUM>) arranged in the board accommodating portion <NUM>. <FIG> is a perspective view of the switch body <NUM> in a state in which the housing Hg is detached to expose the board accommodating portion <NUM> as viewed obliquely from the front. <FIG> is an exploded perspective view of the electromagnet <NUM> and the housing Hg, and is a view of the switch body <NUM> as viewed from the rear.

Referring to <FIG>, a part of a yoke portion of the electromagnet <NUM> is formed in a raised shape, and the protrusion 130b is formed by the raised portion although not particularly limited. The switch body <NUM> can be attached such that an attachment portion 103b is located on the side although being attached such that the protrusion 130b is located at the top in the arrangement example illustrated in <FIG>.

As can be seen from <FIG> and <FIG>, the protrusion 130b protruding in the Z-axis direction has the two screw holes 130c separated at the front and rear, that is, in the Y-axis direction, and is fixed to the first bracket <NUM> having the L-shaped cross section using screws Sc threaded into the two screw holes 130c (<FIG>).

Referring to <FIG> and <FIG>, the first board Cb(<NUM>) and the second board Cb(<NUM>) are accommodated in the board accommodating portion <NUM>, and the first board Cb(<NUM>) and the second board Cb(<NUM>) are disposed in an orthogonal state. Specifically, the first board Cb(<NUM>) is arranged in an attitude so as to have a plate surface along the Y-axis direction, and the second board Cb(<NUM>) is arranged in an attitude so as to have a plate surface along the Z-axis direction. The second board Cb(<NUM>) is preferably arranged in a state of hanging down from the first board Cb(<NUM>) at a rear end portion of the first board Cb(<NUM>) when described in the state illustrated in <FIG>.

As described above, the switch body <NUM> includes at least the display unit <NUM> (<FIG>, <FIG>, and <FIG>) that performs display corresponding to the safety-related output that is output from the switch body <NUM>.

The display unit <NUM> is provided at a position visible from a side opposite to a surface of the switch body <NUM> where the screw holes 130c as the attachment portions are located. That is, the display unit <NUM> is provided at a position visible from the side where the attachment surface formed by the top surface of the protrusion 130b does not exist. When the switch body <NUM> is fixed to the door opening frame <NUM>, the screw holes 130c are arranged and fixed so as to extend to the outer side from the opening formed in the door opening frame <NUM>. Thus, a surface on the side opposite to the surface where the screw holes 130c are provided is arranged toward the inner side of the opening. In the example of <FIG>, the switch body <NUM> is fixed to the upper side horizontal frame portion 2b of the door opening frame <NUM>, a direction from the opening to the outer side is upward. Then, since the inner side of the opening is the lower side for the upper side horizontal frame portion 2b, the surface on which the display unit <NUM> is provided faces the lower side. In a case where the switch body <NUM> is fixed to a frame portion (a right frame portion on the paper surface of <FIG>) of the door opening frame <NUM> on a side opposite to a side where the hinge <NUM> is provided although being fixed to the upper side horizontal frame portion 2b of the door opening frame <NUM> forming the opening in the present embodiment, the display unit <NUM> is located on the left side on the paper surface of <FIG>. Since the display unit <NUM> is provided on the side opposite to the screw hole 130c in this manner, the display unit <NUM> faces the side of the door opening frame <NUM> opposite to the frame portion to which the switch body <NUM> is attached, that is, the inner side of the opening. In a case where the operation region S is viewed from the outer side of the door PD having the transparent board <NUM>, the transparent board <NUM> is located on the inner side of the opening, and thus, the switch body is visible from the inner side of the opening. Thus, the visibility of the display unit <NUM> is improved as the display unit <NUM> is located on the inner side of the opening when being fixed to the door opening frame <NUM>.

As can be clearly seen from <FIG>, the display unit <NUM> has a shape continuously extending in the circumferential direction of the switch body <NUM>, and extends from a surface on a side opposite to the attachment portion 103b in the Z-axis direction to an intermediate portion in the Z-axis direction of side surfaces facing each other in the X-axis direction. As a result, the worker who views the operation region S from the outside can visually recognize the display unit <NUM> not only from below but also from the side when description is given with reference to the installation example of <FIG>. This visibility can be improved by providing the display unit <NUM> with a curved cross-sectional shape as disclosed in <FIG>, and can be improved by providing the display unit <NUM> with a shape continuously extending in the circumferential direction of the switch body <NUM>. Further, an outer surface of the display unit <NUM> has a tapered shape toward the attracting surface 130a in the Y-axis direction as can be clearly seen from <FIG> in order to enhance the visibility.

Referring to <FIG>, in the board accommodating portion <NUM>, a limited illumination space Ls is formed by the first board Cb(<NUM>) whose plate surface extends from the front to the rear, that is, along the Y-axis direction, and the second board Cb(<NUM>) whose plate surface extends along the Z-axis direction. Then, light of an LED <NUM> mounted on the second board Cb(<NUM>) is emitted toward the limited illumination space Ls, and as a result, is displayed through a light transmissive material forming a part of the display unit <NUM> and forming a part of the housing Hg. Of course, the LED <NUM> forming a light source may be provided on the first board Cb(<NUM>).

As described above, the switch body <NUM> is arranged inside the operation region S. A lighting state of the display unit <NUM> is visible from the outer side of the openable and closable door PD through the transparent board <NUM> (<FIG>) of the openable and closable door PD. The visibility of the display unit <NUM> when the switch body <NUM> is viewed from the outside will be described with reference to <FIG> is a schematic view created to describe the visibility of the display unit <NUM>. In the drawing, reference sign Ey denotes an eye of the worker.

In <FIG>, reference sign <NUM>-<NUM> denotes a display unit located proximal to the attracting surface 130a. That is, a distance D-<NUM> between the attracting surface 130a and the display unit <NUM>-<NUM> in the Y-axis direction is relatively small. Reference sign <NUM>-<NUM> denotes a display unit located distal to the attracting surface 130a.

A distance D-<NUM> between the attracting surface 130a and the display unit <NUM>-<NUM> in the Y-axis direction is relatively large.

As can be understood from <FIG>, it can be seen that the display unit <NUM> has better visibility when the display unit <NUM> is viewed from the outside through the openable and closable door PD in the case of being arranged distally rather than proximally of the attracting surface 130a. Preferably, the display unit <NUM> is arranged at the rear of an intermediate line Imd including an intermediate line Imd having a half length of the total length L (<FIG>) of the switch body <NUM> in the Y-axis direction.

A control circuit that generates a drive signal of the electromagnet <NUM>, a power supply circuit, a communication circuit with the actuator <NUM>, and the like are mounted on a body Cb(body) of the first board Cb(<NUM>). On the other hand, an indicator lamp control circuit and the like are mounted on the second board Cb(<NUM>).

Referring to <FIG>, in the board accommodating portion <NUM>, the first board Cb(<NUM>) whose plate surface extends along the Y-axis direction has a pair of left and right board extensions Cb(1ex) that are long and thin and extend in the Y-axis direction to the vicinity of the attracting surface 130a from the body Cb(body) which is located in the board accommodating portion <NUM> and on which the control circuit and the like are mounted. The pair of board extensions Cb(1ex) is located on both sides of the protrusion 130b interposed therebetween in the X-axis direction. With the configuration in which the pair of board extensions Cb(1ex) is located on both the sides of the protrusion 130b, the presence of the board extensions Cb(1ex) can prevent an increase in a height dimension of the switch body <NUM> in the Z-axis direction. Further, a part of the board extension Cb(1ex) is arranged at a position overlapping the electromagnet <NUM> as viewed in the Z-axis direction. Thus, the presence of the board extensions Cb(1ex) can reduce an increase in the dimensions of the switch body <NUM> in the Z-axis direction and the X-axis direction.

In the pair of board extensions Cb(1ex), a sensor-side coil (antenna coil) <NUM> is mounted at a distal end portion of one board extension Cb(1ex) (<FIG>). The sensor-side coil <NUM> constitutes a detection unit that detects the presence of the actuator <NUM> within a predetermined range with respect to the switch body <NUM>. Since the sensor-side coil <NUM> is mounted at the distal end portion of the one board extension Cb(1ex), the sensor-side coil <NUM> can be located close to the attracting surface 130a in the Y-axis direction. As a result, the detection capability of the sensor-side coil <NUM> can be enhanced. As is well known, the sensor-side coil <NUM> is arranged to correspond to the actuator communication unit <NUM> of the actuator <NUM> described above. At this time, the sensor-side coil <NUM> is covered with the housing Hg made of plastic, instead of metal, in order for the sensor-side coil <NUM> to detect the actuator communication unit <NUM>. Thus, in the switch body, a part of the housing Hg is present on a surface facing the actuator <NUM> in addition to the attracting surface 130a. In the present embodiment, the workability through the door opening frame <NUM> in which the switch body <NUM> is arranged can be maintained by arranging a part of the housing Hg in the dead space as described above.

For example, in a process of closing the door PD, the iron piece <NUM> of the actuator <NUM> approaches the attracting surface 130a of the switch body <NUM> in conjunction with the closing operation of the door PD, and then, the iron piece <NUM> overlaps the attracting surface 130a of the switch body <NUM>. The diameter D1 (<FIG>) of the iron piece <NUM> (the surface to be attracted 120a) is designed to be a value larger than a diameter D2 of the attracting surface 130a. Based on a state in which the iron piece <NUM> overlaps the switch body <NUM> in a normal state, that is, the normal state in which a center O1 of the iron piece <NUM> and a center O2 of the attracting surface 130a are aligned, the diameter D1 of the iron piece <NUM> is set relative to the diameter D2 of the attracting surface 130a such that an outer edge of the attracting surface 130a is located within the surface to be attracted 120a of the iron piece <NUM>. As a result, even when the switch body <NUM> and/or the actuator <NUM> are/is relatively displaced in an allowable manner, the switch body <NUM> can fix the actuator <NUM> with a predetermined attracting force.

In the closed state of the door PD, that is, when the sensor-side coil <NUM> detects the actuator communication unit <NUM>, the safety-related output is output to, for example, a PLC that controls the apparatus installed in the operation region S (<FIG>) when another condition is satisfied. An RFID detection circuit (not illustrated) related to the sensor-side coil <NUM> is mounted on the board extension Cb(1ex) of the first board Cb(<NUM>), and the electromagnet <NUM> is controlled based on a signal from the sensor-side coil (antenna coil) <NUM>.

<FIG> is a block diagram for describing an electrical configuration of the switch body <NUM>. The control circuit <NUM> of the switch body <NUM> includes a first MCU <NUM> and a second MCU <NUM>. The first MCU <NUM> and the second MCU <NUM> communicate with each other to monitor the counterpart.

The first MCU <NUM> is connected to a transmission circuit <NUM>. The transmission circuit <NUM> is connected to the sensor-side coil (antenna coil) <NUM>. The sensor-side coil <NUM> is connected to a reception circuit <NUM>. The reception circuit <NUM> is connected to both the first MCU <NUM> and the second MCU <NUM>. The first MCU <NUM> drives the sensor-side coil <NUM> via the transmission circuit <NUM>, and supplies a radio signal from the sensor-side coil <NUM> to the actuator communication unit <NUM>. The actuator communication unit <NUM> includes at least a coil and a circuit, and is arranged such that the coil is located in a portion covered with the plastic molding <NUM> as illustrated in <FIG>. The first MCU <NUM> and the second MCU <NUM> receive the radio signal from the actuator communication unit <NUM> via the sensor-side coil <NUM> and the reception circuit <NUM>. The RFID <NUM> includes the sensor-side coil <NUM> and a response circuit. The actuator communication unit <NUM> may be a radio tag (RF-ID tag). The response circuit operates using an induced current generated in the sensor-side coil <NUM> as a power supply. The response circuit demodulates the radio signal received by the sensor-side coil <NUM> to acquire information, and further transmits a radio signal (response signal) via the sensor-side coil <NUM>.

Referring to <FIG>, each of a measurement unit 210a of the first MCU <NUM> and a measurement unit 210b of the second MCU <NUM> measures the intensity of the radio signal from the actuator communication unit <NUM> received via the sensor-side coil <NUM> and the reception circuit <NUM>, and estimate a distance d between the switch body <NUM> and the actuator <NUM> based on the intensity of the radio signal. Each of a safety determination circuit 214a of the first MCU <NUM> and a safety determination circuit 214b of the second MCU <NUM> determines that the estimated distance d is equal to or smaller than a threshold, that is, whether or not the actuator <NUM> is within a predetermined range with respect to the switch body <NUM>. In other words, the detection unit that detects that the actuator <NUM> is within the predetermined range with respect to the switch body <NUM> is realized by at least the sensor-side coil <NUM>, the reception circuit <NUM>, and the first MCU <NUM> or the second MCU <NUM>. Note that, instead of the distance d, the intensity of the radio signal may be used as it is to detect a position of the actuator <NUM>. A demodulation unit 212a of the first MCU <NUM> and a demodulation unit 212b of the second MCU <NUM> demodulate information conveyed by radio signals from the actuator communication unit <NUM> received via the sensor-side coil <NUM> and the reception circuit <NUM>, respectively, and identify the actuator <NUM> based on the information. This information may include unique identification information.

The safety determination circuit 214a of the first MCU <NUM> determines whether or not two conditions are satisfied based on the measurement by the measurement unit 210a and the identification by the demodulation unit 212a, that is, a condition that the estimated distance d is equal to or smaller than the threshold and a condition that the actuator <NUM> is identified as a predetermined actuator, and transmits a determination result to the second MCU <NUM>. More specifically, there are two types of determination results, that is, a result that both the conditions are satisfied and a result that at least one of the conditions is not satisfied. Similarly, the safety determination circuit 214b of the second MCU <NUM> determines whether or not two conditions are satisfied based on the measurement by the measurement unit 210b and the identification by the demodulation unit 212b, that is, a condition that the estimated distance d is equal to or smaller than the threshold and a condition that the actuator <NUM> is identified as the predetermined actuator, and transmits a determination result to the first MCU <NUM>. The safety determination circuit 214a of the first MCU <NUM> outputs a safety-related output determining that the actuator <NUM> identified as the predetermined actuator is in the predetermined range with respect to the switch body <NUM>, that is, the door PD is in the closed state when the self-determination result matches the determination result of the second MCU. Similarly, the safety determination circuit 214b of the second MCU <NUM> determines that the actuator <NUM> identified as the predetermined actuator is in the predetermined range with respect to the switch body <NUM>, that is, the door PD is in the closed state when the self-determination result matches the determination result of the first MCU. Note that the first MCU <NUM> and the second MCU <NUM> output the safety-related output via an output signal switching device (OSSD) when a condition related to a signal input via an input circuit <NUM> is also satisfied as will be described later in the present embodiment, but the safety-related output may be output based on the radio signal received via the reception circuit <NUM> and the mutual determination results of the first MCU <NUM> and the second MCU <NUM>. Further, the estimation of the distance d between the switch body <NUM> and the actuator <NUM> and the identification of the actuator <NUM> are performed based on the radio signal detected by the sensor-side coil <NUM> in the present embodiment, but it may be configured such that only the estimation of the distance d is performed, and the safety determination circuit 214a or 214b outputs the determination result as to whether the distance d is equal to or smaller than the threshold to the other safety determination circuit without performing the determination related to the identification of the actuator <NUM>.

Returning to <FIG>, the input circuit <NUM> includes a first safety input unit <NUM>, a second safety input unit <NUM>, and a lock input unit <NUM>. Another device capable of outputting a safety-related output is connected to the first safety input unit <NUM> and the second safety input unit <NUM>. That is, the first safety input unit <NUM> and the second safety input unit <NUM> are input circuits configured for a daisy chain connection between the switch body <NUM> and the other device. For example, in the first safety input unit <NUM> and the second safety input unit <NUM>, one of terminals for outputting the safety-related output of the other device is connected to the first safety input unit <NUM>, and the other terminal for outputting a safety-related output of the other device is connected to the second safety input unit <NUM>.

The lock input unit <NUM> is connected to an external control device such as a safety PLC and a safety control device, receives a lock signal for controlling the lock mechanism output from the external control device, and outputs the input signal to the second MCU <NUM>. The second MCU <NUM> determines whether or not the signal input via the lock input unit <NUM> is an ON signal. The second MCU <NUM> can drive the electromagnet <NUM> based on the lock signal input via the lock input unit <NUM> to attract the electromagnet <NUM> to the iron piece <NUM> of the actuator <NUM>. That is, the door PD is locked by the magnetic force in accordance with the signal input via the lock input unit <NUM>. Note that the second MCU <NUM> may drive the electromagnet <NUM> when the signal input via the lock input unit <NUM> is the ON signal, or may drive the electromagnet when it is determined that another condition is satisfied in addition to the condition that the signal input via the lock input unit <NUM> is the ON signal. For example, the above-described determination by the safety determination circuits 214a and 214b may be a condition for driving the electromagnet <NUM>. In this case, the electromagnet <NUM> is driven when it is determined that the predetermined actuator <NUM> is in the state of being within the predetermined range with respect to the switch body <NUM>, the reliability that the door PD maintains the closed state is improved by the lock signal output from the external control device.

The control circuit <NUM> includes a first OSSD 230a and a second OSSD 230b as a switching device <NUM>. The first MCU <NUM> outputs the safety-related output via the first OSSD 230a, and the second MCU <NUM> outputs the safety-related output via the second OSSD 230b. Note that an external device to which the safety-related output is output via the first OSSD 230a and the second OSSD 230b and the external control device that outputs the lock signal input via the lock input unit <NUM> may be the same device or different devices, and both of them constitute the compartment system <NUM>.

The first OSSD 230a and the second OSSD 230b are configured using, for example, PNP transistors. When the PNP transistor is turned on, a positive-side power supply is connected to an output terminal, and thus, an ON signal is output. On the other hand, when the PNP transistor is turned off, the output terminal is grounded via a pull-down resistor, and thus, an OFF signal is output.

An OSSD monitoring circuit <NUM> may be connected to each of the first OSSD 230a and the second OSSD 230b. The OSSD monitoring circuit <NUM> is connected to the first MCU <NUM> and the second MCU <NUM>. The first MCU <NUM> monitors whether or not the second OSSD 230b normally operates through the OSSD monitoring circuit <NUM>. The second MCU <NUM> monitors whether or not the first OSSD 230a normally operates through the OSSD monitoring circuit <NUM>. For example, each of the first OSSD 230a and the second OSSD 230b periodically shifts the output signal to OFF for a minute time when outputting the ON signal. The OSSD monitoring circuit <NUM> determines that the OSSD is normal if OFF for the minute time can be detected during an output period of the ON signal, and determines that the OSSD is not normal if OFF for the minute time is not detectable.

Note that a case where OFF for the minute time is not detectable by the OSSD monitoring circuit <NUM> and the ON signal continues is caused by, for example, a short circuit between the output terminal and the positive-side power supply. In this case, the safety determination circuits 214a and 214b output control signals for outputting the OFF signals to the first OSSD 230a and the second OSSD 230b, respectively. As a result, a normally operating one of the first OSSD 230a and the second OSSD 230b outputs the OFF signal. Note that the shift of the safety-related output to OFF for monitoring the OSSD monitoring circuit <NUM> is set to such a minute time that the external device to which the safety-related output is output does not react to this OFF.

A power supply circuit <NUM> is a DC-DC converter that receives DC+<NUM> V and <NUM> V from the outside and generates DC voltages such as DC +<NUM> V, +<NUM> V, and +<NUM> V. The power supply circuit <NUM> supplies power to all circuits that require power, such as the control circuit <NUM>, the sensor-side coil <NUM>, and the display unit <NUM>. Meanwhile, in a case where a voltage supplied from an external power supply or a voltage output from the power supply circuit <NUM> is not within a predetermined range, there is a possibility that the control circuit <NUM> or the like does operate normally. Therefore, the power supply monitoring circuit <NUM> determines whether or not the voltage supplied from the external power supply is within the predetermined range, determines whether the voltage output from the power supply circuit <NUM> is within the predetermined range, and outputs a determination result to the first OSSD 230a and the second OSSD 230b. When a determination result indicating that the power supply circuit <NUM> is not operating normally is input, each of the first OSSD 230a and the second OSSD 230b sets the safety-related output to OFF without depending on the control signal output from the control circuit <NUM>. When a determination result indicating that the power supply circuit <NUM> is normally operating is input, each of the first OSSD 230a and the second OSSD 230b outputs the safety-related output depending on the control signal output from the control circuit <NUM>.

The control circuit <NUM> includes an indicator lamp control unit <NUM> that controls the display unit <NUM>, and the indicator lamp control unit <NUM> of the second MCU <NUM> supplies the indicator lamp control unit <NUM> with at least a display state signal according to the safety-related output via the second OSSD 230b. A relationship between ON or OFF of the safety-related output and determination results in the first MCU <NUM> and the second MCU <NUM> will be described with reference to <FIG>.

A column "Indicator lamp" in <FIG> indicates a light emission pattern of the display unit <NUM> controlled based on the display state signal supplied to the indicator lamp control unit <NUM>. A column "State" is subdivided into "OSSD" and "Safety input", "Lock control input", and "Actuator". The column "OSSD" indicates whether the safety-related output, which is output to the external control device via the first OSSD 230a and the second OSSD 230b as the switching device <NUM>, is ON or OFF. Further, the columns "Safety input", "Lock control input", and "Actuator" indicate determination items used when determining whether to set the safety-related output, which is output via the switching device <NUM>, to ON or OFF. The column "Safety input" indicates whether the safety-related output, input via the first safety input unit <NUM> and the second safety input unit <NUM>, is ON or OFF.

The column "Lock control input" indicates whether the lock signal input from the external control device via the lock input unit <NUM> is ON or OFF. The column "Actuator" indicates whether or not the actuator <NUM>, which is identified as the predetermined actuator based on the radio signal received via the sensor-side coil <NUM> and the reception circuit <NUM>, has been detected to be in the predetermined range with respect to the switch body <NUM>.

As illustrated in <FIG>, in the present embodiment, the safety-related output, which is output via the switching device <NUM>, is set to ON when the safety-related output input via the first safety input unit <NUM> and the second safety input unit <NUM> is ON, the lock signal input via the lock input unit <NUM> is ON, and the actuator <NUM> has been detected. At this time, the light emission pattern of the display unit <NUM> is lighting in green. Further, when the actuator <NUM> is not detected, regardless of the safety-related output and the lock signal input via the first safety input unit <NUM> and the second safety input unit <NUM>, the safety-related output, which is output via the switching device <NUM> set to OFF, and the light emission pattern of the display unit <NUM> is lighting in red. The safety switch <NUM> of the present embodiment detects whether the actuator <NUM> is within the predetermined range with respect to the switch body <NUM> in order to maintain the operation region S in the safe environment. When the actuator <NUM> is not detected, the door PD is not in the closed state, and the operation region S is not maintained as the safe environment. Thus, regardless of input states of other signals, the safety-related output, which is output via the switching device <NUM>, is set to OFF.

In addition to the detection of the actuator <NUM>, the safety switch <NUM> of the present embodiment refers to input states of various signals and determines whether to set the safety-related output, which is output via the switching device <NUM>, to ON or OFF. At this time, as compared with the detection by the actuator <NUM>, it is difficult for the worker to grasp which state the safety-related output or the lock signal input via the first safety input unit <NUM> and the second safety input unit <NUM> is in. More specifically, whether or not the actuator <NUM> is detected has a certain correlation with whether or not the door PD is in the closed state. Thus, in a case where the actuator <NUM> is not detected and the safety-related output, which is output from the switch body <NUM> via the switching device <NUM>, is set to OFF, the worker can easily specify the cause thereof. On the other hand, regarding the safety-related output or the lock signal input via the first safety input unit <NUM> and the second safety input unit <NUM>, the worker can confirm whether or not the cable corresponding thereto is connected and the like by appearance, but hardly grasps any state of the signal supplied via such a cable by appearance. Thus, in the present embodiment, when the safety-related output that is output via the switching device <NUM> is OFF due to input states of various signals, the light emission pattern of the display unit <NUM> is changed according to the input states of the various signals in the present embodiment such that the worker can easily specify the reason why the safety-related output, which is output from the switch body <NUM> via the switching device <NUM>, is OFF.

Note that, in the present embodiment, the safety-related output that is output from the switch body <NUM> and the light emission pattern of the display unit <NUM> are changed according to the column "Safety input" in <FIG> since the other device capable of outputting the safety-related output is connected to the first safety input unit <NUM> and the second safety input unit <NUM>. However, in a case where the other device is not connected, the safety-related output that is output from the switch body <NUM> and the light emission pattern of the display unit <NUM> may be determined according to the column "Lock control input" and the column "Actuator". In this case, when the column "Lock control input" is "ON" and the column "Actuator" is "Detected", the safety-related output that is output by the switch body <NUM> is set to ON, and the light emission pattern of the display unit <NUM> is lighting in green. Further, in this case, there is no case where the light emission pattern of the display unit <NUM> is "orange" or "blinking in orange" as illustrated in <FIG>.

As described above, the distance d (<FIG>) from the switch body <NUM> to the actuator <NUM> is estimated based on the intensity of the radio signal. When the distance d is within the predetermined range, an ID is acquired from the actuator communication unit <NUM>, it is confirmed that the acquired ID matches a recorded ID, and then, it is determined whether or not the electromagnet <NUM> and the iron piece <NUM> are in close contact with each other.

The determination as to whether or not a distance d2 is equal to or smaller than a threshold will be specifically described with reference to <FIG>. The second MCU <NUM> supplies an inspection current to the electromagnet <NUM>, and monitors a current flowing through the electromagnet <NUM> at this time. In <FIG>, (I) illustrates a rectangular wave of the inspection current. A value of the inspection current is smaller than a value of a lock current supplied to the electromagnet <NUM> to maintain the closed state of the door PD, that is, to form a locked state of the safety switch <NUM>. If a current having the same value as the value of the lock current is adopted for inspection, even if the lock signal is not ON, the electromagnet <NUM> attracts the iron piece <NUM> with an attracting force enough to maintain the door PD in the closed state, and thus, an operation of opening the door PD is hindered, and the workability of the worker is deteriorated. In this regard, when the value of the inspection current is set to a value smaller than the value of the lock current, particularly to a weak value to such an extent that the electromagnet <NUM> hardly exhibits the attracting force, the workability of the worker can be maintained.

In <FIG>, (II) illustrates a monitoring current flowing to the electromagnet <NUM> to correspond to the inspection current of the rectangular wave in (I) of <FIG> in a state in which the electromagnet <NUM> and the iron piece <NUM> are not in close contact with each other, that is, a state in which the distance d2 between the attracting surface 130a and the surface to be attracted 120a is larger than a threshold. In <FIG>, (III) illustrates a monitoring current flowing to the electromagnet <NUM> to correspond to the inspection current of the rectangular wave in (I) of <FIG> in a state in which the electromagnet <NUM> and the iron piece <NUM> are in close contact with each other, that is, a state in which the distance d2 between the attracting surface 130a and the surface to be attracted 120a is equal to or smaller than the threshold. As can be seen from comparison between (II) and (III) in <FIG>, in the state in which the electromagnet <NUM> and the iron piece <NUM> are in close contact with each other, that is, the state in which the distance d2 between the attracting surface 130a and the surface to be attracted 120a is equal to or smaller than the threshold, an inductance is higher than that in the state in which the distance d2 is larger than the threshold. Thus, the period of time from a time point at which the supply of the inspection current has been started to a time point at which a value of the monitoring current reaches a certain value increases.

When there is a difference in the period of time until the value of the monitoring current reaches a certain value from the time point when the supply of the inspection current has been started, there is a difference in a value of a current flowing through the electromagnet <NUM> at a timing when a certain period of time has elapsed since the start of supply of the inspection current. For the comparison between (II) and (III) in <FIG>, the timing when a certain period of time has elapsed since the start of supply of the inspection current to the electromagnet <NUM> is illustrated as an inspection confirmation timing. A value of a current at the inspection confirmation timing of the monitoring current flowing through the electromagnet <NUM> in the state in which the distance d2 between the attracting surface 130a and the surface to be attracted 120a is larger than the threshold is a first monitoring current value I1 illustrated in (II) of <FIG>. Further, a value of a current at the inspection confirmation timing of the monitoring current flowing through the electromagnet <NUM> in the state in which the distance d2 between the attracting surface 130a and the surface to be attracted 120a is equal to or smaller than the threshold is a second monitoring current value I2 illustrated in (III) of <FIG>. When comparing the first monitoring current value I1 and the second monitoring current value I2, the first monitoring current value I1 is larger. That is, the monitoring current ((II) in <FIG>) reaching the certain value for a shorter period of time since the time point when the inspection current has been supplied, in other words, the monitoring current having higher responsiveness has a larger current value at the inspection confirmation timing than the monitoring current ((III) in <FIG>) having lower responsiveness. Therefore, by comparing values of the monitoring current at the inspection confirmation timing, it is possible to discern whether the responsiveness of the monitoring current flowing through the electromagnet <NUM> is high or low, whether the inductance associated with the level of the responsiveness is high or low, and whether the distance d2 between the attracting surface 130a and the surface to be attracted 120a associated with the magnitude of the inductance is long or short. More specifically, a threshold value of a current value is set at least between the first monitoring current value I1 and the second monitoring current value I2 such that the magnitude relationship between the distance d2 and the threshold can be discerned, and it is determined whether the distance d2 is larger than the threshold or equal to or smaller than the threshold depending on whether the current value of the monitoring current at the inspection confirmation timing is larger than the threshold value or equal to or smaller than the threshold value.

<FIG> is a longitudinal cross-sectional view of the actuator <NUM>. <FIG> illustrates the actuator <NUM> attached to the door PD in which the door frame <NUM> is attached so as to be parallel to the door opening frame <NUM> to which the switch body <NUM> is attached in the mode of <FIG>. Thus, a normal direction of the door frame <NUM> (PD) coincides with the Y-axis direction as a normal direction of the attracting surface 130a of the electromagnet <NUM> included in the switch body <NUM>. Furthermore, the actuator <NUM> in <FIG> is in a state in which a normal direction of the surface to be attracted 120a of the iron piece <NUM> included in the actuator <NUM> coincides with the Y-axis direction.

Referring to <FIG>, the attachment fitting <NUM> described above forms a base member of the actuator <NUM>. The attachment fitting <NUM> has a U-shaped cross-sectional shape having flanges at both ends, and includes a through hole 126a at the center of a planar top portion. The actuator <NUM> includes a movable pin <NUM> inserted into the through hole 126a of the attachment fitting <NUM>, and one end portion of the movable pin <NUM> is fixed to the iron piece <NUM>. The iron piece <NUM> includes a permanent magnet 120b having a circular shape in a front view at a center portion of the surface to be attracted 120a. The movable pin <NUM> inserted into the through hole 126a of the attachment fitting <NUM> is movable relative to the attachment fitting <NUM> in an axial direction of the movable pin <NUM>. With this configuration, a movement mechanism that relatively moves the surface to be attracted 120a with respect to the attachment fitting <NUM> is configured.

The movable pin <NUM> includes a pin head 320a located at an end on the attachment fitting <NUM> side. The movable pin <NUM> is inserted into a sleeve <NUM>. The sleeve <NUM> has a length in the axial direction of the movable pin <NUM>, and has a first-end flange 322a and a second-end flange 322b which extend radially outward and circumferentially. The first-end flange 322a and the second-end flange 322b of the sleeve <NUM> are used to set a constant position of the iron piece <NUM> with respect to the movable pin <NUM>, and the iron piece <NUM>, the movable pin <NUM>, and the sleeve <NUM> move with respect to the attachment fitting <NUM>.

The movable pin <NUM> and the sleeve <NUM> are movable in the axial direction of the movable pin <NUM> as an outer circumferential surface of the sleeve <NUM> is guided to the through hole 126a. The sleeve <NUM> has a guide function of guiding the movement of the movable pin <NUM> in the axial direction. The movable pin <NUM> is also swingable inside the through hole 126a together with the sleeve <NUM>. That is, a diameter of the sleeve <NUM> is smaller than a diameter of the through hole 126a, and the sleeve <NUM> is loosely fitted into the through hole 126a. With this configuration, a swing mechanism for swinging the surface to be attracted 120a is configured.

A compression coil spring <NUM> is provided between the first-end flange 322a of the sleeve <NUM> and the attachment fitting <NUM>. The compression coil spring <NUM> constitutes a biasing unit that biases the movable pin <NUM> and the surface to be attracted 120a in a direction approaching the door frame <NUM>, that is, in a retracting direction.

In <FIG>, (I) is a plan view of the compression coil spring <NUM>. In <FIG>, (II) is a side view of the compression coil spring <NUM> in an unloaded state. In <FIG>, (III) is a side view of the compression coil spring <NUM> in a state of being compressed as a load is applied. As can be seen from (I) of <FIG>, the compression coil spring <NUM> is configured using a spiral spring having a trapezoidal shape in the side view with a diameter gradually reduced in an axial direction.

The compression coil spring <NUM> having a spiral shape can have a flat shape in the side view in the compressed state. Thus, a moving range when the movable pin <NUM> moves is expanded in a direction in which the compression coil spring <NUM> is compressed.

In the present embodiment, the state of the actuator <NUM> illustrated in <FIG>, that is, a state in which the iron piece <NUM> has been moved in the direction approaching the door frame <NUM>, in other words, in a direction away from the electromagnet <NUM> by the compression coil spring <NUM> is defined as a standby state, and a position of the iron piece <NUM> in this state is defined as a standby position. Note that modifications of the compression coil spring <NUM> can include an elastic body such as a disc spring or rubber.

A cushion member <NUM> is disposed between the second-end flange 322b of the sleeve <NUM> and the attachment fitting <NUM> and the iron piece <NUM> (<FIG>). As will be described later, an impact when the iron piece <NUM> overlaps the attracting surface 130a of the electromagnet <NUM> based on an attractive force of the permanent magnet 120b is alleviated by the compression coil spring <NUM> and the cushion member <NUM>.

<FIG> is a view for describing an action of the actuator <NUM>. In <FIG>, (I) illustrates the actuator <NUM> in the standby state, and corresponds to <FIG>. Note that the actuator communication unit <NUM> in <FIG> indicates a position of an actuator coil included in the actuator communication unit <NUM>.

In <FIG>, (II) illustrates a state in which the actuator <NUM> has approached the attracting surface 130a of the electromagnet <NUM> included in the switch body <NUM> as the door PD is closed in a process in which the door PD is changed from an open state to the closed state, that is, in a process in which the worker closes the door PD. At this time, the electromagnet <NUM> is not driven. As illustrated in (II) of <FIG>, when the actuator <NUM> approaches the electromagnet <NUM>, the attractive force by the permanent magnet 120b included in the actuator <NUM> acts on the attracting surface 130a of the electromagnet <NUM>. When the attractive force becomes larger than a spring force of the compression coil spring <NUM>, the compression coil spring <NUM> starts to be compressed. Then, under the attractive force of the permanent magnet 120b, the movable pin <NUM> and the iron piece <NUM> move together with the plastic molding <NUM> in the direction away from the door frame <NUM>, that is, in the direction approaching the attracting surface 130a. Therefore, for example, when the door PD is closed and the distance between the actuator <NUM> and the switch body <NUM> falls within a certain range, the movable pin <NUM> and the iron piece <NUM> move together with the plastic molding <NUM> in the direction approaching the attracting surface 130a along the Y-axis direction. According to this configuration, a relative position of the surface to be attracted 120a with respect to the attachment fitting <NUM> is offset toward the attracting surface 130a side when the actuator <NUM> is out of the predetermined range with respect to the switch body <NUM> as compared with that at the time when the actuator <NUM> is within the predetermined range with respect to the switch body <NUM>. Thus, a close contact state between the surface to be attracted 120a and the attracting surface 130a is easily realized. Further, according to this configuration, the actuator communication unit <NUM> is offset toward the attracting surface 130a side together with the surface to be attracted 120a relative to the attachment fitting <NUM>. That is, a distance between the actuator communication unit <NUM> and the sensor-side coil <NUM> when the attracting surface 130a and the surface to be attracted 120a come into contact with each other becomes constant regardless of a position of the surface to be attracted 120a in the actuator <NUM>. Thus, it is possible to determine whether or not the actuator <NUM> is within the predetermined range with respect to the switch body without setting the threshold to be compared with the distance d according to the position of the surface to be attracted 120a in the actuator <NUM>.

In <FIG>, (III) illustrates a state in which the surface to be attracted 120a and the attracting surface 130a are brought into close contact with each other by the attractive force of the permanent magnet 120b through the process of (II) described above. The threshold for the distance d is set such that the distance d estimated based on the intensity of the radio signal received from the actuator communication unit <NUM> via the sensor-side coil <NUM> in this state is equal to or smaller than the threshold, that is, such that the actuator communication unit <NUM> determines that the actuator <NUM> is within the predetermined range with respect to the switch body <NUM> in this state. Further, in the state of (III) of <FIG>, the second MCU <NUM> supplies a detection current to the electromagnet <NUM> and monitors a current flowing through the electromagnet <NUM>, thereby determining whether or not the surface to be attracted 120a and the attracting surface 130a are in close contact with each other. When it is determined that the surface to be attracted 120a and the attracting surface 130a are in close contact with each other, the second MCU <NUM> drives the electromagnet <NUM> to attract the iron piece <NUM> to maintain the closed state of the door PD. Note that, in the present embodiment, the iron piece <NUM> moves to the attracting surface 130a side by the attractive force of the permanent magnet 120b included in the actuator <NUM> so that the attracting surface 130a and the surface to be attracted 120a are brought into close contact with each other in the closed state of the door PD. However, the movement of the iron piece <NUM> to the attracting surface 130a side may be realized by another unit. For example, it may be configured such that the iron piece <NUM> moves to the attracting surface 130a side by inertia when the door PD is set to the closed state, that is, when the door PD is closed. Further, the electromagnet <NUM> may be configured such that the electromagnet <NUM> is driven to generate an attracting force weaker than an attracting force for maintaining the closed state of the door PD, and the iron piece <NUM> moves to the attracting surface 130a side by the attractive force.

<FIG> is a cross-sectional view for describing a state change of the actuator <NUM>. In <FIG>, (I) corresponds to (I) of <FIG>, and the actuator <NUM> is in the standby state. In <FIG>, (II) illustrates a state in which the iron piece <NUM> of the actuator <NUM> has advanced to the maximum to be set at a maximum action position, that is, a state in which the movable pin <NUM> is set at a maximum stroke position displaced in the axial direction, that is, the Y-axis direction. This state can be created by the attractive force of the permanent magnet 120b. In <FIG>, (III) is a view for describing that the iron piece <NUM> is swingable to obtain a state in which the surface to be attracted 120a is parallel to the attracting surface 130a when the iron piece <NUM> and the attracting surface 130a overlaps each other under the attractive force of the permanent magnet 120b. The parallel state between the surface to be attracted 120a and the attracting surface 130a is established by swinging, that is, a tilting motion of an axial line Ax of the movable pin <NUM>.

As described above, the actuator communication unit <NUM> is disposed in the plastic molding <NUM> surrounding the periphery of the iron piece <NUM> is disposed with (<FIG>). On the other hand, the sensor-side coil <NUM> is disposed in the switch body <NUM> (<FIG>). It is determined whether the actuator <NUM> is within the predetermined range with respect to the switch body <NUM>, that is, whether or not the distance d is equal to or smaller than the threshold based on the intensity of the radio signal received from the actuator communication unit <NUM> via the sensor-side coil <NUM>.

<FIG> is a flowchart for describing power supply control of the electromagnet <NUM> by the second MCU <NUM> in a process of closing the door PD. When the door PD is open, the electromagnet <NUM> is not supplied with power (S1). In a process in which the door PD is set to the closed state, that is, closed, the actuator <NUM> approaches the switch body <NUM>. In Step S2, whether or not the distance d between the surface to be attracted 120a and the attracting surface 130a is within a predetermined value is determined between the actuator communication unit <NUM> and the sensor-side coil <NUM>. When it is determined in Step S2 that the distance d is within the predetermined value, the flow proceeds to Step S3 to determine whether or not the distance d2 is equal to or smaller than the threshold. When it is determined in Step S3 that the distance d2 is equal to or smaller than the threshold, the flow proceeds to Step S4. In Step S4, power is supplied to the electromagnet <NUM> on a condition that another condition is satisfied. When the electromagnet <NUM> is driven, the actuator <NUM> is attracted to the electromagnet <NUM> by an electromagnetic force of the electromagnet <NUM>, and the door PD is set to an electromagnetically locked state. Note that, in the present embodiment, control is performed such that power is not supplied to the electromagnet <NUM> in Step S1, and control is performed such that power is supplied to the electromagnet <NUM> in Step S4. However, any configuration may be adopted in which the electromagnet <NUM> is controlled so as to generate an attracting force sufficient to maintain the door PD in the closed state according to a determination result in Step S3. For example, the electromagnet <NUM> may be driven so as to generate an attracting force smaller than the attracting force sufficient to maintain the door PD in the closed state in Step S1, and control may be performed to increase the attracting force to an extent sufficient to maintain the door PD in the closed state in Step S4.

Modifications that do not include all features of the invention will be described below with reference to <FIG>.

In a first modification <NUM> illustrated in <FIG>, which does not include all features of the invention, the actuator <NUM> is fixed to the door frame <NUM> with a mounting tool <NUM>. The mounting tool <NUM> has a guide surface Gf that guides the actuator <NUM> in advancing and retracting directions, that is, the Y-axis direction, and the actuator <NUM> is guided by the guide surface Gf inside the mounting tool <NUM>, is displaceable in the Y-axis direction, and can move forward to approach the attracting surface 130a of the electromagnet <NUM>. The actuator <NUM> is biased in a retracting direction away from the electromagnet <NUM> by an elastic body <NUM> such as a coil spring. In a power-off state of the electromagnet <NUM>, the actuator <NUM> moves forward in the Y-axis direction against a biasing force of the elastic body <NUM> by the attractive force of the permanent magnet 120b located at a center portion of the iron piece <NUM>, and then, a state in which the surface to be attracted 120a and the attracting surface 130a are in a close contact with each other is formed under the attractive force of the permanent magnet 120b.

<FIG> illustrates a second modification <NUM>, which does not include all features of the invention. In the second modification <NUM>, only the electromagnet <NUM> included in the switch body <NUM> can move forward to approach the permanent magnet 120b of the actuator <NUM> in the Y-axis direction by the guide surface Gf. The electromagnet <NUM> is biased in the retracting direction by an elastic body <NUM> such as a coil spring. In the power-off state of the electromagnet <NUM>, the electromagnet <NUM> moves forward in the Y-axis direction against a biasing force of the elastic body <NUM> by the attractive force of the permanent magnet 120b, and then, a state in which the surface to be attracted 120a and the attracting surface 130a are in close contact with each other is formed under the attractive force of the permanent magnet 120b.

<FIG> illustrates a third modification <NUM>, which does not include all features of the invention. In the third modification <NUM>, a movable member <NUM> and an elastic body <NUM> such as a coil spring are disposed between the switch body <NUM> and the first bracket <NUM>. The movable member <NUM> is displaceable in the Y-axis direction by the guide surface Gf. The switch body <NUM> is fixed to the movable member <NUM>. When the movable member <NUM> is displaced in the Y-axis direction, the switch body <NUM> moves in the Y-axis direction together with the displacement, and can move forward to approach the iron piece <NUM> of the actuator <NUM>. The movable member <NUM> is biased in the retracting direction by an elastic body <NUM> such as a coil spring. In the power-off state of the electromagnet <NUM>, the electromagnet <NUM> moves forward together with the movable member <NUM> against a biasing force of the elastic body <NUM> by the attractive force of the permanent magnet 120b of the iron piece <NUM>, and then, a state in which the surface to be attracted 120a and the attracting surface 130a are in close contact with each other is formed under the attractive force of the permanent magnet 120b.

In a fourth modification <NUM> illustrated in <FIG>, which does not include all features of the invention, the switch body <NUM> is movable relative to the first bracket <NUM>. The switch body <NUM> is guided by the guide surface Gf and is displaceable in the Y-axis direction. Then, in the switch body <NUM>, the switch body <NUM> is biased in the retracting direction by an elastic body <NUM> such as a coil spring. In the power-off state of the electromagnet <NUM>, the electromagnet <NUM> moves forward together with the movable member <NUM> against a biasing force of the elastic body <NUM> by the attractive force of the permanent magnet 120b of the iron piece <NUM>, and then, a state in which the surface to be attracted 120a and the attracting surface 130a are in close contact with each other is formed under the attractive force of the permanent magnet 120b.

Furthermore, in each of the first modification to the fourth modification described above, which do not include all features of the invention, an object moving in the Y-axis direction may be swingably held. For example, in the first modification <NUM>, the actuator <NUM> that moves relative to the mounting tool <NUM> may be swingably held with respect to the mounting tool <NUM>.

Claim 1:
A safety switch (<NUM>) comprising:
a switch body (<NUM>) arranged in a compartment fixed portion (PF) of a compartment system (<NUM>) that comparts an operation region (S) in which an apparatus operates; and
an actuator (<NUM>) installed in a movable portion (PD) movable relative to the compartment fixed portion (PF), the safety switch (<NUM>) detecting that the actuator (<NUM>) is within a predetermined range with respect to the switch body (<NUM>),
wherein the actuator (<NUM>) includes:
a member (<NUM>) to be magnetized on which a surface to be attracted (120a), which corresponds to an attracting surface (130a) formed on an electromagnet (<NUM>) provided in the switch body (<NUM>), is formed,
characterized in that the actuator (<NUM>) further includes:
an actuator attachment portion (<NUM>) configured to attach the actuator (<NUM>) to the movable portion (PD); and
a movement mechanism which supports the member (<NUM>) to be movable relative to the actuator attachment portion (<NUM>) to set a relative position of the surface to be attracted (120a) of the member (<NUM>) with respect to the actuator attachment portion (<NUM>) at a position offset toward the attracting surface (130a) of the switch body (<NUM>) when the actuator (<NUM>) is in the predetermined range with respect to the switch body (<NUM>) as compared with a position when the actuator (<NUM>) is not in the predetermined range with respect to the switch body (<NUM>), wherein
the movement mechanism includes:
a through hole (126a) provided in the actuator attachment portion (<NUM>);
a movable pin (<NUM>) that has one end to which the member (<NUM>) to be magnetized is fixed, is inserted into the through hole (126a), and is movable in an axial direction relative to the through hole (126a); and
a sleeve (<NUM>) into which the movable pin (<NUM>) is inserted, the sleeve (<NUM>) moving with movement of the movable pin (<NUM>), and
movement of the member (<NUM>) toward the electromagnet (<NUM>) is guided by the through hole (126a) and the sleeve (<NUM>).