EP1856706B1 - Command switch, in particular an emergency stop switch - Google Patents

Abstract

A command switch or and emergency stop switch is disclosed, which includes an actuator and a contact sensor which is separated therefrom. The actuator includes housing and a tappet, which is guided therein and which has a rest position and an actuation position. The contact sensor includes an open switch element which can be placed in the actuation position by way of the tappet in a tensed position. In at least one embodiment, the command switch also includes an additional switch element which is provided with a first switch piece and a second switch piece, which are applied to the actuator in a separated manner and in/on the contact sensor. The additional switch element only closes when the contact sensor is secured to the actuator. The switch pieces of the additional switch element are separated from each other in a compulsory and advantageous manner by the separated embodiment of the command switch enabling them to be secured to different components of the command switch. An axial or radial misalignment, tilting or rotation between the actuator and the contact sensor leads to the non-conductive connection of the contact piece.

Description

The invention relates to a command switch, in particular an emergency-stop switch, with an actuator and a contactor separately designed for this, which can be fastened to the actuator. The actuator has a housing and a guided in this ram with a rest and operating position. The contactor comprises an opener-switching element, which can be brought in the operating position by means of the plunger in an open position.

The command switch may e.g. be an emergency stop switch, which has a cup-shaped or mushroom-shaped red cap. Usually, the cap is bolted to the plunger. If the command switch is actuated, the plunger of the actuator is brought from the rest position to the operating position. The plunger thereby forcibly interrupts the contacts of the normally closed switching element, so that the circuit, e.g. a connected electrical machine is interrupted. In addition, in the contactor - depending on the application - be further housed opener and closer switching elements, which are actuated together via the plunger.

The European standard EN 418 "Safety of machinery" from 1992 also specifies the safety requirements for EMERGENCY STOP devices. In point 4.1.2. is described that the command device and its actuator must operate on the principle of forced operation. A forced opening switch is e.g. a suitable command device.

Alternatively, the state of the normally closed switching element can also be interrogated by a monitoring device in which, for example, a bit pattern is coupled via the closed normally closed contacts of the normally closed switching element and continuously receives the received signal Result is checked. Such a monitoring device is, for example, the ASI-F monitoring device of the company. Siemens. This device is also bus-capable, so that in the absence of the expected bit pattern via a bus data technically achievable plant parts can be brought into a safe state.

The command switch is also made in two parts. The separability is therefore required to close the command switch by means of the actuator e.g. to attach to a cabinet door, front panel or panel. For this example, the actuator for mounting by a relatively small hole in a cabinet door o.ä. guided and firmly connected by means of a fastening nut or a clamping ring with this. Subsequently, the contactor on the actuator, usually by means of a snap or screw, be attached. As a result, the live parts of the command switch, e.g. housed in the control cabinet.

If the attachment of the contactor to the actuator is not performed properly, e.g. because the contactor is not snapped properly, or has the screw solved by vibration, the contactor can be released from the actuator, without this being noticed. An EMERGENCY STOP circuit then remains closed despite the EMERGENCY STOP switch being actuated. The EMERGENCY STOP switch thus loses its functionality and thus its protective function. This can lead to unpredictable damage to people and plant components in control systems.

From the DE 41 01 493 A1 For example, a command switch or an emergency stop switch is known, which allows monitoring of the function of the contactor.

The disadvantage is that the contacts of a closer provided there to weld the monitoring of the contactor or stick together, so that a release of the contactor by the actuator is not noticed because the contacts of the shutter remain closed.

A further disadvantage is that a contact spring provided for the normally open contact which holds the closer open when inactive can break. Also in this case, the release of the contactor from the actuator is not recognized.

The document " WO 2004/023501 A "discloses a strobe switch according to the preamble of claim 1.

It is therefore an object of the invention to provide a command switch, in which an improper attachment of the contactor on the actuator is securely detected.

The object of the invention is achieved with a command switch, in particular with an emergency stop switch, which has an actuator and a contactor attachable to the actuator. The actuator has a housing and a guided in this ram with a rest and actuation position. The contactor comprises an opener-switching element, which can be brought in the operating position by means of the plunger in an open position. In addition, the command switch has a further switching element with a first contact piece and a second contact piece, which is mounted separately on the actuator and / in the contactor. The further switching element closes only, i. becomes electrically conductive if the contactor is properly fastened to the actuator.

The great advantage of the invention is that the separate execution of the command switch forcibly the switching pieces of the other switching element are separated from each other, since they are attached to different components of the command switch. In particular, the further switching element and the command switch are made in two parts. The other switching element is therefore only functional and operational if the two parts - actuator and contactor - are properly secured together. An axial or radial offset, a tilting or rotation between the actuator and contactor then cause the contacts of the contact pieces with each other no conductive connection.

Compared to the prior art advantageous spot welds or bonds to the contacts of the contact pieces are "torn apart", so to speak, in which the detached contactor "takes along" the respective contact of its contact piece.

In a first embodiment, the switching pieces of the further switching element are arranged opposite one another. For this purpose, either the first or the second switching piece is attached to the contactor side facing the housing side of the actuator, while the second or the first contact piece is mounted in or on the contactor. This advantageously provides a good opportunity for aligning the switching pieces to each other.

In a preferred embodiment, the normally closed switching element and a switching piece of the further switching element are arranged on a printed circuit board in the contactor. The arrangement of these electrical components, in addition to the mechanical fixation in or on the contactor also an electrical connection, such. a series connection of the electrical contacts of different switching elements with each other, in a simple manner possible. In addition, the circuit board can be easily inserted into a suitable recess in the contactor.

In a further embodiment of the invention, the first contact piece of at least two contact pins and the second contact piece are formed from a contact bridge. The contact bridge may be an electrical conductor or a contacting surface in the simplest case. In the correctly installed state of the contactor, bridged at the actuator this contact bridge the two pins. For example, these two contact pins can also be led to an outside of the contactor for external wiring.

Alternatively, the two contact pins can also be accommodated in the housing of the actuator, wherein the contact pins are then to be electrically connected to each other. On the side of the contactor two contact surfaces can be attached, which each face a contact pin. The contacting surfaces can e.g. small circular designated areas on a circuit board, which are continued, for example, to the external terminals to the outside of the contactor.

By using contact pins as a part of the other switching element extremely accurate contacting is possible. If the contacting surface or the contacting surfaces of the contact bridge are only slightly larger in relation to the cross-sectional area of a contact pin, advantageously smallest assembly errors such as radial offsets, tilting, etc. can be detected immediately. In these cases, a pin tip is no longer electrically connected to a contacting surface.

The contact pins are preferably sprung contacted, for example, they have a travel of 1 mm. This can e.g. be achieved by a mechanical stop in the contact pin. Due to the resilient force of the contact pins, a sufficient and constant contacting force between contact pin and contact bridge or contacting surface is advantageously achieved. Possible manufacturing tolerances for the actuator and contactor are compensated.

In a further advantageous embodiment, the normally closed switching element and the further switching element are electrically connected in series. For external wiring are still advantageous only two terminals to lead. The additional Function of the assembly monitoring is integrated in the command switch according to the invention.

Finally, the contactor can be snapped on an advantageous simple manner on the actuator, locked or screwed. In the event of a fault, a contactor detected as defective can be unlocked and replaced.

FIG 1

einen Längsschnitt durch einen beispielhaften NOT- AUS-Schalter mit einem weiteren Schaltelement gemäß der Erfindung,

FIG 2

einen Längsschnitt durch einen weiteren beispielhaf- ten NOT-AUS-Schalter mit auf einer Leiterplatte ange- ordneten Schaltelementen gemäß einem Ausführungsbei- spiel der Erfindung,

FIG 3

ein beispielhaftes Schaltbild zur Überwachung von zwei NOT-AUS-Stromkreisen nach dem Stand der Technik, und

FIG 4

ein beispielhaftes Schaltbild zur Überwachung von zwei NOT-AUS-Stromkreisen mit einem herkömmlichen und einem erfindungsgemäßen NOT-AUS-Schalter gemäß FIG 1 oder FIG 2.

The invention will be explained in more detail with reference to the following figures. It shows

FIG. 1

a longitudinal section through an exemplary emergency stop switch with another switching element according to the invention,

FIG. 2

3 a longitudinal section through a further exemplary EMERGENCY STOP switch with switching elements arranged on a printed circuit board according to an exemplary embodiment of the invention,

FIG. 3

an exemplary circuit diagram for monitoring two emergency-stop circuits according to the prior art, and

FIG. 4

an exemplary circuit diagram for monitoring two emergency stop circuits with a conventional and an emergency stop switch according to the invention according to FIG. 1 or FIG. 2 ,

FIG. 1 shows a longitudinal section through an exemplary EMERGENCY STOP switch. In the upper part of the figure, an actuator 1 is shown, the housing 4 is inserted in an opening of an exemplary front panel 2. For reasons of clarity, the illustration of a clamping ring for fastening the actuator 1 to the front panel 2 has been dispensed with. In the actuator 1, a plunger 5 is guided, which firmly connected at an upper end with an emergency stop cap 3 is. The actuator 1 and the plunger 5 have a rest and an actuating position. The actuation position can be seen on the dashed representation of the lower edge of the EMERGENCY STOP cap 3. When pressure on the EMERGENCY STOP cap 3, the registered in the figure actuating travel s sets. This distance is transmitted to the same extent via the plunger 5.

In the lower part of the figure, a box-shaped contactor 6 is further shown, which is snapped example of the actuator 1. The reference numeral 10 indicates the position of locking lugs which engage in corresponding openings in the housing 4 of the actuator 1. After snapping the contactor 6 is positively connected via an exemplary support frame 11 with the actuator 1. The lower end of the plunger 5 now acts on a known per se NC switching element 8. In the operating position, a contact bridge 83 of two contacts 81, 82 is separated. In this way, an emergency stop circuit, which is guided via two external connection contacts 91, 92, interrupted.

According to the invention, a further switching element 7 is now provided, which consists of a first 71, 72 and a second contact piece 73. In the example of the figure, two contact pins 71, 72 form the first contact piece. Both are firmly connected to the housing of the contactor 6, wherein the contact pins 71, 72 protrude through corresponding openings in the holder frame 11. The two contact pins 71, 72 are already performed resilient according to an embodiment of the invention. The second switching piece 73 is in the example of the figure, a contact bridge, which is attached to the lower end of the housing 4 of the actuator 1.

In the mounted state of the contactor 6 are now the two contact pins 71, 72 opposite the contact bridge 73. Contact pins 71, 72 and contact bridge 73 are aligned and arranged so that according to the invention only in properly assembled state, a conductive connection between the two pins on the contact bridge 73 is made.

According to a preferred embodiment of the invention, the normally closed switching element 8 and the further switching element 7 are electrically connected in series. This has already happened in the example of the figure. About the two external terminals 91, 92 thus an emergency stop detection as well as an assembly monitoring of the contactor 6 on the actuator 1 is possible.

FIG. 2 shows a longitudinal section through another exemplary EMERGENCY STOP switch with arranged on a circuit board 13 switching elements 7 ', 81', 82 '. The contactor 6 'is already shown attached to the housing 4' of the actuator 1 '. In the contactor 6 'holding webs 12 for receiving and fixing the circuit board 13 are provided. With the reference numerals 81 'and 82' two Öffnerkontakte a normally closed switching element symbolized. By means of a respective plunger 51, 52 which are mechanically fixed to one another, the NC contacts 81 ', 82' can be forcibly opened in the event of an EMERGENCY STOP. In addition to the NC contacts 81 ', 82' are also two contact pins 71 ', 72' mounted on the circuit board 13 and soldered there. In the properly mounted state of the contactor 6 ', the two contact pins 71', 72 'electrically conductively connected via a contact bridge 73'. The normally closed contacts 81 ', 82' and the contact pins 71 ', 72' are interconnected in series, so that via the external terminal contacts 91 ', 92' an emergency stop detection and mounting monitoring of the contactor 6 'on the actuator 1 ' is possible.

FIG. 3 shows a circuit diagram for monitoring two emergency-stop circuits according to the prior art. A monitoring device 14 monitors, by way of example, an EMERGENCY STOP switch with two NC switching elements 8, 16. Monitoring of a contactor 6, 6 'to a proper assembly is not possible in this case.

FIG. 4 shows an exemplary circuit diagram of an emergency stop circuit with a conventional and an emergency stop switch according to the invention according to FIG. 1 and FIG. 2 , Another monitoring device 15 monitors by way of example an emergency stop switch with two normally closed switching elements 8, 16 and each a further switching element 7. The further switching element 7 carries according to its function the circuit-technical symbol of an opener. The series connection according to the invention, an emergency stop detection and detection of a not properly mounted contactor 6, 6 'possible. In both cases, the relevant EMERGENCY STOP circuit is opened so that an electrical machine or other parts of the system can be switched off safely.

Alternatively, the contacts of a normally closed switching element 81, 81 ', 82, 82' and another switching element 71, 71 ', 72, 72', 73, 73 'may also be separately, i. not in series, to external connection contacts on the contactor 6, 6 'are laid. In this case, a monitoring device can separately monitor the detection of an EMERGENCY STOP and the detection of a non-properly mounted contactor.

Claims (7)

1. Command switch, in particular an EMERGENCY-OFF switch,

   - having an actuator (1) which has a housing (4) and a plunger (5), which is guided therein, with a rest position and an operated position,

   - having a contact maker (6), which can be attached to the actuator (1) and has a break switching element (8), wherein, when the break switching element (8) is in the operated position, it can be moved to an open position by means of the plunger (5), characterized in that

   - the command switch is provided with a further switching element (7), and the switching element is provided with a first switching piece (71,72) and a second switching piece (73), which are fitted separately in the actuator (1) and in the contact maker (6), such that the further switching element (7) is closed when the contact maker (6) is correctly attached to the actuator (1).
2. Command switch according to Claim 1, in which the contact pieces (71, 73) of the further switching element (7) are arranged opposite.
3. Command switch according to Claim 1 or 2, in which the break switching element (8) and a contact piece (71, 72) of the further switching element (7) are arranged on a printed circuit board (13) in the contact maker (6).
4. Command switch according to one of the preceding claims, in which the first contact piece (71, 72) is formed from at least two contact pins, and the second contact piece (73) is formed from a contact link.
5. Command switch according to Claim 4, in which the contact pins (71, 72) make sprung contact.
6. Command switch according to one of the preceding claims, in which the break switching element (8, 16) and the further switching element (7) are electrically connected in series.
7. Command switch according to one of the preceding claims, in which the contact maker (6) can be snapped, locked or screwed to the actuator (1).

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