Patent Application
20140220802
This invention relates generally to lockout and tagging devices and assemblies and, in particular, to lockout and tagging devices and assemblies for switchable energy isolation devices such as terminal blocks.
Different types of machinery in the workplace do their work by means of energy—electrical, mechanical, hydraulic, or pneumatic, etc. Releasing this energy makes the machines run. which is very useful, but not if the energy is released at the wrong time or if one is in the way.
There are many examples of people being seriously injured or killed by machinery and electrical equipment. Often, these tragedies happen because people carelessly try to repair or maintain the equipment without making sure its energy source has been shut off. Many times the accident happens when another worker restarts the machine, not knowing that another worker is in the machine. To prevent this type of tragedy, OSHA developed a standard that has very specific procedures for shutting off machinery, for making sure it cannot be operated after it has been shut off, and for warning employees to stay away from potential hazards. These procedures are called lockout/tagout.
The OSHA standard for The Control of Hazardous Energy (Lockout/Tagout), Title 29 Code of Federal Regulations (C.F.R.) Part 1910.147, addresses the practices and procedures necessary to disable machinery or equipment, thereby preventing the release of hazardous energy while employees perform servicing and maintenance activities. The standard outlines measures for controlling hazardous energies—electrical, mechanical, hydraulic, pneumatic, chemical, thermal, and other energy sources.
In addition, 29 C.F.R. 1910.333 sets forth requirements to protect employees working on electric circuits and equipment. This section requires workers to use safe work practices, including lockout and tagging procedures. These provisions apply when employees are exposed to electrical hazards while working on, near, or with conductors or systems that use electric energy.
The lockout/tagout standard establishes the employer's responsibility to protect employees from hazardous energy sources on machines and equipment during service and maintenance.
The standard gives each employer the flexibility to develop an energy control program suited to the needs of the particular workplace and the types of machines and equipment being maintained or serviced. This is generally done by affixing the appropriate lockout or tagout devices to energy-isolating devices and by de-energizing machines and equipment. The standard outlines the steps required to do this.
Lockout means much more than simply shutting of a machine by throwing a switch. When a machine has been locked out, it means:
all energy to the machine has been shut off (there may be more than one type of energy);
any energy that has been stored has been released or blocked; and
the machine is literally locked out and cannot be restarted or released accidentally.
In lockout, a lock is placed on the part of the machine that controls the energy, such as a circuit breaker, switch, or valve. The lock itself cannot be used for any other purpose. That means you cannot use just any lock you might find in the workplace to perform a lockout—in fact, all lockout locks should be of the same general appearance so people can easily recognize them for what they are (for example, by color, brand, etc.). The lock must be strong and sturdy enough to stay in place until it is time for it to be unlocked.
Terminal blocks or strips such as terminal blocks of Phoenix Contact GmBH & Co. KG and others can be found in large numbers in electrical power plants. Such blocks or strips (boards) typically include an insulating base or slab equipped with one or more terminal connectors for the purpose of making electrical connections thereto. Many such blocks can switch according to different switching principles.
Such blocks or strips typically have 120 VAC or 130 VDC running through them to power instrumentation and control (I+C) equipment. Such equipment needs to be maintained and, consequently, the circuit on which the equipment is located needs to be de-energized prior to any such maintenance, to protect such workers. Such blocks may also include one or more female receptacles or jacks to receive a test plug of electronic test and measurement instruments to measure an electrical parameter of the circuit.
One possible way of de-energizing the circuit on which the equipment is located is to remove a wire or wires from the block. As shown in
Many terminal blocks are “switchable” to open the circuit without removing any wiring by having a slide or sliding link. As shown in
Also, as a way of providing a visual indication to others that the circuit was de-energized, a tag was often hung from live wiring to provide such visual indication. Ideally, it is desirable to hang such a tag form the terminal block. However, such terminal blocks typically do not provide a convenient location to hang such tags and, consequently, were oftentimes not hung. As a result, maintenance personnel often worked on equipment that was either not tagged or was energized. Neither situation was desirable.
An object of at least one embodiment of the present invention is to provide a lockout and tagging device and assembly for an energy isolation device such as a switchable terminal block to improve the safety of workers who are performing routine service and maintenance tasks on equipment.
In carrying out the above object and other objects of at least one embodiment of the present invention, a lockout and tagging device for a switchable energy isolation device is provided. The isolation device has a female receptacle and a moveable actuator for switching the isolation device between isolating and non-isolating states. The lockout and tagging device includes a base member configured to support a tag and a male member extending from the base member and including a retaining portion complementary to the receptacle to retain the male member in the female receptacle after insertion of the male member into the female receptacle. The device also includes a blocking member extending from the base member. The blocking member positively blocks the actuator from moving and switching the isolation device into its non-isolating state when the male member is retained in the female receptacle. A circuit coupled to the isolation device is positively de-energized when the actuator is blocked in the isolating state of the isolation device by the blocking member.
The female receptacle may include a banana-type jack having a conductive sleeve with the internal bore and the male member may be a banana-type plug to provide a low-resistance compression fit with the jack.
The switch may include a control element slidable on a track having an opening. A distal end of the blocking member may extend into the opening to block the control element from moving from an open position to a closed position of the control element.
The distal end of the blocking member may be generally cylindrical wherein the opening is sized and shaped to allow the distal end to fit into the opening and block the control element in the open position.
The male and blocking members may have central axes which are substantially parallel to each other.
The base and blocking members may be made of a non-conductive material such as a laminated plastic material.
The blocking member and the base member may be integrally formed from the laminated plastic material.
The device may be a two-pronged device wherein the blocking and male members are prongs of the device.
The base member may include at least one aperture extending completely therethrough to receive a locking strip.
Further in carrying out the above object and other objects of at least one embodiment of the invention, a lockout and tagging assembly for a switchable, energy isolation device is provided. The device has a female receptacle and a movable actuator for switching the device between isolating and non-isolating states. The assembly includes a warning tag, a base member to suspend the tag and a male member extending from the base member and including retaining portion complementary to the receptacle to retain the male member in the receptacle after insertion of the male member into the receptacle. The assembly also includes a blocking member extending from the base member. The blocking member positively blocks the actuator from moving and switching the device into its non-isolating state when the male member is retained in the female receptacle. A circuit coupled to the device is positively de-energized when the actuator is blocked in the isolating state of the device by the blocking member. The tag provides a visual warning that the circuit has been de-energized and should not be energized.
The female receptacle includes a banana-type jack having a conductive sleeve with an internal bore and the male member may be a banana-type plug to provide a low-resistance compression fit with the jack.
The actuator includes a control element slidable on a track having an opening wherein a distal end of the blocking member extends into the opening to block the control element from moving from an open position to the closed position of the control element.
The distal end of the blocking member may be generally cylindrical wherein the opening is sized and shaped to allow the distal end to fit into the opening and block the control element in the open position.
The male and blocking members may have central axes which are substantially parallel to each other.
The base and blocking members may be made of a non-conductive material such as a laminated plastic material.
The blocking member and the base member may be integrally formed from the laminated plastic material.
The base member may have at least one aperture extending completely therethrough to receive a locking strip. The locking strip may support the tag from the base member.
The male and blocking members may form two prongs extending from one end of the base member.
Still further in carrying out the above object and other objects of at least one embodiment of the present invention, a lockout and tagging device for a switchable terminal block is provided. The block has a female receptacle with a pin-receiving internal bore and a switch that is actuated by moving a control element from an open position to a closed position. The device includes a base member configured to support a tag and a male pin member extending from one end of the base member and including at least one radially-resilient conductor portion complementary to the internal bore to lock the pin member in the female receptacle after insertion of the pin member into the female receptacle. The device also includes an electrically-insulating blocking member extending from the one end of the base member. The blocking member positively blocks the control element from moving from the open position to the closed position when the pin member is locked in the female receptacle. A circuit electrically coupled to the terminal block is positively de-energized when the control element is blocked in the open position.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
A lockout and tagging device for a switchable energy isolation device such as a terminal block is provided. The energy is typically electrical energy but may be mechanical, hydraulic, pneumatic, chemical, thermal, and other energy sources.
Typically, a bank or a row of such blocks is provided in a power plant as shown in
Referring now to
The device 20 further includes an electrically-insulating blocking member 30 extending from the one end 26 of the base member 22. The blocking member 30 positively blocks the control element 16 from moving from the open position to the closed position when the pin member 24 is positively locked in the female receptacle 12. A circuit (not shown) electrically coupled to the terminal block 10 is positively de-energized when the control element 16 is blocked in its open position as shown in
The female receptacle 12 is preferably a banana-type jack having a conductive sleeve with the internal bore and the pin member 24 is preferably a banana-type plug to provide a low-resistance compression fit with the jack.
The switch 14 is preferably a slide switch wherein the control element 16 slides on the track 15 having the opening 19. A distal end 32 of the blocking member 30 extends into the opening 19 to block the control element 16 from moving from its open position to the closed position.
The distal end 32 of the blocking member 30 is generally cylindrical and wherein the opening 19 is sized and shaped to allow the distal end 32 to fit into the opening 19 and block the control element 16 in its open position as shown in
The pin and blocking members 24 and 30, respectively, have central axes which are substantially parallel to each other and form two prongs. The device 20 is preferably a two-pronged device wherein the block and pin members 24 and 30, respectively, are prongs of the device.
The base member 22 is preferably made of a non-conductive material such as a laminated plastic material having a trade name of Micarta. The blocking member 30 and the base member 22 are preferably integrally formed by machining the laminated plastic material.
As shown in
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
This application claims the benefit of U.S. provisional Patent Application entitled “Electrical Lockout Device” filed Feb. 2, 2013 and having Application No. 61/760,061.
| Number | Date | Country | |
|---|---|---|---|
| 61760061 | Feb 2013 | US |
