Emergency safety switch

An emergency safety switch for a safety control system used to terminate the operation of one or more automated machines includes a stop circuit that is electrically connected to a connection port. The connection port includes a pair of interface ports for in-line serial connection to a wiring circuit provided by the safety control system to monitor various emergency safety switch and other detection devices. As such, the connection port provides a quick and easy manner for attaching and detaching the emergency safety switch to the wiring circuit, which facilitates efforts to install a sufficient number of emergency stop switches on an automated production line.

TECHNICAL FIELD

The present invention relates generally to an emergency safety switch for automated machinery. More particularly, the present invention relates to an emergency safety switch configured for use with existing safety circuit wiring provided by a safety control system. More specifically, the present invention relates to an emergency safety switch having a connection port to facilitate the attachment of the emergency safety switch to existing safety circuit wiring provided by a safety control system.

BACKGROUND ART

Emergency safety switches, emergency stops, or E-stops are typically part of a comprehensive safety control system that is utilized to supervise the operation of automated production systems, such as those used, for example, for automated manufacturing. Specifically, the safety control system is in communication with one or more emergency safety switches and with various pieces of automated machinery that is part of the automated production line. In response to the actuation of the emergency safety switch to indicate that an unsafe event has occurred or is about to occur, the safety control system stops or terminates the operation of the automated machinery in order to prevent the occurrence of injury to workers, the machinery, or to the articles being handled by the machinery. Thus, emergency safety switches or E-stops are provided as manually-actuated switches, which are actuated by a worker when he or she identifies or anticipates an unsafe condition and needs to stop the automated movement of the production line machinery.

Current emergency stop switches or E-stop switches are required to be hardwired into the safety circuit wiring of the safety control system, which requires substantial time and effort to carry out. In the case of existing safety control systems that utilize proprietary wiring configurations, it can take an inexperienced technician a significant amount of time and effort to understand the wiring logic of such wiring configurations in order to correctly attach the emergency safety switch or E-stop to the safety system wiring. Such drawbacks may result in the lack of a sufficient number of emergency safety switches or E-stops being installed along the automated production line or, in some cases, the complete lack of the installation of any emergency safety switches altogether.

Therefore, there is a need for an emergency safety switch, or E-stop, that is configured to be easily retrofit or attached to the wiring of an existing safety control system for the machinery of an automated production line or process. In addition, there is a need for an emergency safety switch, or E-stop, that is low cost.

SUMMARY OF INVENTION

It is thus an object of one aspect of the present invention to provide an emergency safety switch that can easily be coupled to a safety control system for machinery in a production line.

It is an object of another aspect of the present invention to provide an emergency safety switch, as above, that can economically be retrofit to existing safety control systems.

These and other objects of the present invention, as well as the advantages thereof over existing prior art forms, which will become apparent from the description to follow, are accomplished by the improvements hereinafter described and claimed.

In general, an emergency safety switch configured to be coupled to a wiring circuit of a safety control system used to terminate the operation of one or more automated machines coupled thereto includes a first path having a first control switch. The emergency safety switch also includes a second path having a second control switch, and a main switch that is in operative communication with the first and second control switches. A first and second connection interface is adapted to be coupled in series with the wiring circuit of the safety control system. Each connection interface has at least four terminals, such that the first and third terminals of the first and second connection interfaces are coupled together by respective first and second bridge lines. As such, the first path is coupled between the fourth terminals of the first and second connection interfaces, and the second path is coupled between the second terminals of the first and second connection interfaces. Thus, when the main switch is actuated, the control switches are moved from a normally closed state to an open state.

A preferred exemplary emergency safety switch for a safety control system made according to the concepts of the present invention is shown by way of example in the accompanying drawing without attempting to show all the various forms and modifications in which the invention might be embodied, the invention being measured by the appended claims and not by the details of the specification.

DETAILED DESCRIPTION OF THE INVENTION

An emergency safety switch is generally referred to by the numeral10in the drawing. It should be appreciated, that the term “emergency safety switch” may be used herein interchangeably with the terms “E-stop” and “emergency stop switch”. Specifically, the emergency safety switch10includes a stop circuit20that is operatively coupled to a connection port30that allows the stop circuit20to be attached to a wiring circuit or harness40that is coupled to a safety control system50that monitors the operational status of the switch10. The safety control system50is configured to be coupled to various automated machinery60that is part of an automated production line, process, or manufacturing line. As such, the actuation of the emergency stop switch10causes the safety control system50to responsively stop the operation of the machinery60to which it is coupled.

Stop circuit20of the emergency safety switch10includes electrical connection terminals100,110,120,130,140, and150. Coupled between terminals100and140are a series of coupled light elements160and light switches170, which form a first path. It should be appreciated that the light element160may comprise any suitable illumination element, such as an LED (light emitting diode), or incandescent light for example. Coupled between terminals110and130is a control switch200, which forms a second path, and coupled between terminals120and150is a control switch210, which forms a third path. In one aspect, the light and control switches170,200,210may comprise push-button type switches that are configured to be moved between an ON and OFF position or state, such that the light switch170is normally in an OFF state or open position, while the control switches200,210are normally in an ON state or closed position. In addition, the movement of the light switch170and control switches200,210from their normal resting position or state is controlled by a main switch or actuator250that is operatively attached to the switches170,200,210. It should be appreciated that the actuator250and switches170,200,210are configured as maintained switches that are configured to remain in either a normal resting state or an active state, and are only moved from one state or the other upon the manual actuation of the actuator250by the user. For example, when the actuator250is configured as a push button and is depressed from its normal resting state, the actuator250and the switches170,200,210are moved to an active state where they remain until the actuator250is manually actuated again by the user, such as by pulling or twisting the actuator250, which results in the actuator and switches170,200,210returning to their normal resting state.

As such, during operation of the emergency safety switch10, when the actuator250is depressed by the user's hand, the light switch170and control switches200,210are moved to their active position or state where they maintained. As a result, the light switch170is moved to an ON or closed position, and the control switches200,210are moved to an OFF or open position. If it is desired to return the actuator250and switches170,200,210to the normal resting state then the actuator250is manually moved back to its normal resting state by pulling or twisting the actuator250backward. As a result, the actuator250and switches170,200,210are moved back to their normal resting state where they are maintained.

The connection port30includes interfaces300and310that allow the emergency safety switch10to be readily coupled in-line or in series with the wiring harness or circuit40. In one aspect, the connection interfaces300and310may be configured as threaded or quick-disconnect connectors that are compatible with counterpart connectors provided by the wiring harness or circuit40. Each interface300and310includes four interface terminals320A-D and330A-D, respectively. Terminals320A and320C of interface300are respectively coupled to terminal330A and terminal330C of interface310by respective wires or bridge lines350and352. Furthermore, interface terminals320A and330A of interfaces300and310are coupled to terminal100of the stop circuit20via wire354, while interface terminals320C and330C of interfaces300and310are coupled to terminal140via wire356. In addition, interface terminals320B and320D of interface300are respectively coupled to terminals120and110of the stop circuit20, while interface terminals330B and330D of interface310are respectively coupled to terminals150and130of the stop circuit20. It should also be appreciated that the stop circuit20and connection port30may be carried by any suitable housing.

The emergency safety switch10is configured to be coupled in-line with the wiring circuit or harness40, which includes four conductive lines or wires: a power wire400; a safety control A wire or line410; a ground (GND) wire420; and a safety control B wire or line430. In one aspect, the power and ground (GND) wires or lines400and420may be coupled to any suitable power source, including a 24 VDC power source for example. The safety control wire A410and safety control wire B430are configured to communicate with the safety control system50that is configured to be interfaced with various machinery60that is part of the production line being monitored.

Thus, to place the emergency safety switch10into operation, the connection port30is attached in-line or in series with each end of the wiring circuit40, denoted as40A and40B, provided by the safety control system50, such that interface300is attached to end40A of the wiring40and interface310is attached to end40B of the wiring40. Once the emergency stop switch10is connected to the safety control system50, the light switch170is maintained in a normally open or OFF position, while the control switches210and220are both maintained in a normally closed or ON position. Upon depressing or otherwise actuating the main switch250by the user to identify an adverse event, such as the malfunction of the machinery60, the light and control switches170,200,210are placed in their active position, such that the light switch170is closed and the control switches200,210are opened. As a result, the light element160is illuminated to indicate that the emergency safety switch10was actuated, while the safety A and safety B control lines410and430of the wiring circuit40are placed in an open circuit state. Specifically, the safety control system50interprets the open circuit state of the control lines410,430as an adverse event, and correspondingly takes corrective action by shutting down or terminating the operation of the necessary machinery60to prevent the furtherance of damage to such machines and/or to prevent injury to persons in the vicinity.

It will, therefore, be appreciated that one advantage of one or more embodiments of the present invention is that an emergency safety switch that provides a connection port is configured to be readily and quickly attached to a wiring circuit provided by a safety control system. Another advantage of the present invention is that the emergency safety switch is configured to be connected to emergency control lines provided by the wiring circuit of a safety control system used to shut down automated machinery in the event of an adverse event. Still another advantage of the present invention is that the emergency safety switch provides a light element to identify that the emergency safety switch has been actuated.

Thus, it can be seen that the objects of the present invention have been satisfied by the structure and its method for use presented above.