A safety apparatus for personnel on an oil drilling rig includes a cylindrical quick disconnect switch having a receptacle and a plunger. The receptacle has an open circuit pair of electrical wires. The plunger is configured to attach to a derrick man. The plunger and the receptacle are configured to mate when the plunger is inserted into the receptacle and to remain frictionally mated until pulled apart. The mating results in closing the circuit between the pair of electrical wires.

BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to safety protection devices and more particularly to methods and apparatus for protecting personnel on an oil drilling derrick. 
         [0002]    Oil and gas exploration has been a hazardous undertaking since it began more than 150 years ago. During modern drilling rig operations, one of the times of greatest risk to personnel is when the rig is either running pipe into the well or pulling pipe out of the well. The “derrick man” is positioned up in the derrick (approximately 30 m) on a standard triple stand derrick. His job is to pull and rack the stands (three lengths of pipe joined together) of pipe into the racking board so the stands can be stored in an orderly arrangement. He is required to extend himself out from the racking board, retrieve the top of the stand, and guide it onto the racking board. The rig is usually equipped with at least one of several fall restraint and fall arrest devices in the event he should fall off the racking board. These could include devices such as a full body harness or fail arrest retracting device. 
         [0003]    At times, the derrick man may forget to or is distracted from attaching to the fall protection system. This lack of attention could cause the derrick man to be severely injured, perhaps even fatally injured. Also, his fall may present a serious hazard to personnel on the rig floor. 
         [0004]    Nevertheless, in normal drilling operations, personnel may be required to be in areas or jobs that are inherently hazardous. There are many safety systems on the market that are or can be effective if they are in proper and continuous use. However, rig operations start and stop repeatedly during any working shift. Thus, it is common for the derrick man to take his safety equipment off and on during his shift for breaks, for comfort while waiting on rig maintenance, to perform other functions that cannot be performed while hooked to the safety gear, or for other reasons. When operations restart, the derrick man may or may not remember to reattach all of his safety gear. 
         [0005]    The person on the rig who is in charge of controlling operations is the driller. The driller cannot see all of the personnel involved in rig operations from his location, including the derrick man who may be located  30   m  above him. Thus, the driller presently has no way of verifying that the derrick man is properly harnessed and ready to work every time rig operations are restarted. 
         [0006]    Every known drilling company has specific policies regarding personnel safety during rig operations. OSHA also has regulations relating to these same issues. Insurance companies providing workers' compensation insurance have requirements for safety equipment that insureds must meet. But ultimately, safety depends upon whether personnel follow company policy and use the provided safety equipment. 
         [0007]    Truly safe operations depend upon each of the rig hands being where they are supposed to be for any given rig operation. Because the driller is rarely, if ever, in a position to verify the location of all of the members of the crew during operations, it would be desirable to provide a comprehensive approach to monitoring crew behavior and location. 
         [0008]    It is thus also be desirable to provide apparatus to make drilling operations safer. It is also desirable to provide apparatus that assist in changing the behavior of personnel to make safety systems more effective. 
       SUMMARY OF THE INVENTION 
       [0009]    In one aspect, some configurations of the present invention therefore provide a safety apparatus for personnel on an oil drilling rig. The safety apparatus includes a cylindrical quick disconnect switch having a receptacle and a plunger. The receptacle has an open circuit pair of electrical wires. The plunger is configured to attach to a derrick man. The plunger and the receptacle are configured to mate when the plunger is inserted into the receptacle and to remain frictionally mated until pulled apart. The mating results in closing the circuit between the pair of electrical wires. 
         [0010]    In another aspect, some configurations of the present invention provide a safety apparatus that includes a quick-disconnect switch. The quick-disconnect switch has at least a first part attachable to a derrick man and a second part located on a drill pipe stand near a piece of safety protection equipment. The quick-disconnect switch is operable by a derrick man to indicate that he or she is in position and protected by the piece of safety protection equipment. A light panel in electrical communication with the quick-disconnect switch is also provided. The light panel is located in a position visible by a driller located under the drill pipe stand and is configured to indicate when the quick-disconnect switch is open or closed by the derrick man. 
         [0011]    In yet another aspect, some configurations of the present invention provide a safety apparatus on an oil derrick. The safety apparatus includes a plurality of radio frequency identification (RFID) tags. Each RFID tag assigned to crew members on the oil derrick. Also provided is a plurality of sensors and/or antennae located on the oil derrick that are configured to track and report the location of each said RFID tag. In addition, a control panel having at least one indicator is provided. The control panel is responsive to the location reports and the indicator or indicators are configured to indicate, to a driller, when needed crew members are present and in locations in which the crew members are supposed to be for an operation of the oil derrick being undertaken. 
         [0012]    It will be appreciated that some configurations of the present invention provide a comprehensive approach to monitoring crew behavior and location. It will also be appreciated that some configurations of the present invention provide apparatus to make drilling operations safer, and/or that assist in changing the behavior of personnel to make safety systems more effective. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a pictorial view of a quick-disconnect switch embodiment. 
           [0014]      FIG. 2  is a close-up pictorial view of the reduced diameter male portion of the switch plunger shown in  FIG. 1 . 
           [0015]      FIG. 3  is an axial cut-away view of the quick-disconnect switch of  FIG. 1 . 
           [0016]      FIG. 4  is a pictorial view into the female portion of the switch receptacle shown in  FIG. 1 . 
           [0017]      FIG. 5  is a pictorial view into the reduced diameter male portion of the switch plunger shown in  FIGS. 1 and 2 . 
           [0018]      FIG. 6  is a pictorial view of the quick-disconnect switch of  FIG. 1  attached to a safety vest on a derrick man. Also shown is a hard hat carrying a radio frequency identification (RFID) tag. 
           [0019]      FIG. 7  is a pictorial view of a portion of an oil derrick on which the derrick man is located while working. 
           [0020]      FIG. 8  is a close up pictorial view of the location at which the derrick man works on the oil derrick of  FIG. 7 . 
           [0021]      FIG. 9  is a pictorial view of the bottom portion of the oil derrick of  FIG. 7 , showing a light panel inside a driller's shelter. 
           [0022]      FIG. 10  is a pictorial schematic diagram of an embodiment of a safety protection system of the present invention. 
       
    
    
       [0023]    The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. 
         [0025]    Referring now to  FIG. 1 , some configurations of the present invention provide a quick-disconnect switch  10  that comprises two generally cylindrical components, namely a plunger  12  and a receptacle  14 . In some embodiments, plunger  12  includes a lateral hole  16  near an outside end  17  of plunger  12 . Hole  16  is provided as an attachment point to allow a strap or loop to enter for attachment of switch  10  to a harness or other item of clothing (not shown in  FIG. 1 ). 
         [0026]    Receptacle  14  includes a first portion comprising a cap  22  having two wires passing therethrough. In  FIG. 1 , these two wires are enclosed in a sheath or plastic tube  19 . Receptacle  14  also has a second, female portion  24  that mates with a reduced diameter, male portion  64  of plunger  12 . To provide a watertight as well as frictional fit, at least one, and in the illustrated embodiment two, rubber O-rings  58  and  60  are fitted into grooves in male portion  64  of plunger  12 . O-rings  58  and  60  are seen to best advantage in  FIG. 2 . In some embodiments, O-rings  58  and  60  may also act to resist the accidental separation of plunger  12  from receptacle  14  due to an air seal formed by the O-rings. 
         [0027]    In some embodiments and referring to  FIG. 3 , a female portion  24  of receptacle  14  has two hollow insulators  26  and  28  passing in an axial direction therethrough. Widened rims  42  and  44  and round fasteners  38  and  40  hold hollow insulators  26  and  28  in place. respectively. Threaded conducting rods  34  and  36  pass internally through insulators  26  and  28 , respectively, and are directly connected to wires  18  and  20 , respectively, using tightened nuts  30  and  32 , respectively. Wires  18  and  20 , when not electrically connected, are an open circuit pair of wires. An opposite end of rods  34  and  36  form electrical contacts or posts  46  and  48 , respectively. Posts  46  and  48  project a slight distance above an internal floor of a hollow portion  62  of receptacle  14  as can readily be seen in the pictorial view of  FIG. 4 . 
         [0028]    Referring again to  FIG. 3 , plunger  12  includes a reduced diameter portion  64  and a full diameter portion  66 . In some embodiments, full diameter portion  66  has the same outside diameter as that of receptacle  14 . Reduced diameter portion  64  is configured to tightly, yet slidingly engage hollow portion  62  of receptacle  14 . A post  50  is embedded in an axis of cylindrical plunger  12 . An e-clip  68  on post  50  holds a retainer  56  against a wall in a hollowed-out portion of plunger  12 . A resilient spongy or compressible disk  54  through which post  50  passes is affixed on one side to a face of retainer  56  facing towards posts  46  and  48 , with a conductive, flat annulus  52  affixed to the other side of disk  54 . Annulus  52  is best seen in the pictorial view of  FIG. 5 . Preferably, conductive, flat annulus  52  comprises a flexible, but resilient, metallic sheet. Together (or separately, in some embodiments), disk  54  and annulus  52  are biased towards posts or terminals  46  and  48  to eliminate the need for posts  46  and  48  to be precisely the same length. One or more O-rings  58  and  60  are seated in grooves around reduced diameter portion  64  of plunger  12  and provide some frictional resistance to the separation of plunger  12  from receptacle  14  or a relatively air-tight seal to provide such resistance, or both. The frictional resistance prevents plunger  12  and receptacle  14  from simply sliding apart, but allows separation to occur easily when plunger  12  and receptacle  14  are pulled apart, either deliberately or when a force pulls on the lanyard or strap through hole  16 . 
         [0029]    In some embodiments and referring again to  FIG. 3 , when plunger  12  is inserted into receptacle  14 , electrical contact is completed between posts  46  and  48  through conductive, flat annulus  52 . Thus, there is a completed electrical path between wires  18  and  20  in this condition. When plunger  12  is pulled from receptacle  14 , this path is broken, and there is no complete electrical path between wires  18  and  20 . Thus, when a lanyard or strap is attached to plunger  12  through hole  16  and wires  18  and  20  are electrically communicating with an alarm system, quick-disconnect switch  10  can be used to indicate an alarm condition by the separation of plunger  12  from receptacle  14 . 
         [0030]    In one embodiment, quick disconnect switch  10  has a diameter of about 27 mm and  FIG. 3 , for this embodiment, is drawn approximately to scale. However, neither the diameter nor the length of quick disconnect switch  10  are critical elements of the present invention. In particular,  FIG. 3  does not necessarily represent either the diameter or the relative dimensions of components of quick disconnect switch in all embodiments of the invention. The dimensions of any particular quick disconnect switch may be left as a design choice to one of ordinary skill in the art upon obtaining an understanding of the present invention from this description and the accompanying drawings. 
         [0031]    In one configuration of the present invention and referring to  FIG. 6 , quick disconnect switch  10  is attached by a lanyard  102  to a safety vest  104  worn by a derrick man  106  or other worker. Lanyard  102  loops through hole  16  (shown in  FIGS. 1 and 2 ) in plunger  12 . Receptacle  14  attaches via cable  19  to electrical equipment not shown in  FIG. 6 . In some embodiments, receptacle  14  is tethered in place to the electrical equipment by cable  19 . When derrick man  106  arrives at a job site, he or she puts on vest  104  (which has lanyard  102  and plunger  12  attached thereto) and inserts plunger  12  into receptacle  14  to provide a “safe” indication to the electrical equipment. When derrick man  106  wants to indicate an “unsafe” condition, he or she pulls plunger  12  from receptacle  14 . In another embodiment, if the worker is pulled, pushed, or otherwise displaced from a safe position, plunger  12  is pulled out of receptacle  14  without further intervention by derrick man  106  by movement of safety vest  104  and lanyard  102 . In the embodiment shown in  FIG. 6 , electrical cable  19  is tied to a safety cable  600  of a connecting device  602  that attaches to safety vest  104  using a first detachable hook  604 . Connecting device  602  itself connects to an anchorage  606  such as an I-beam using a second hook  608  (not necessarily easily detachable) and an anchorage connector  610  that is affixed to an anchorage  606 . Cable  19  can also be attached to anchorage  606  and routed to electrical equipment (not shown in  FIG. 6 ). In this particular embodiment and in some other embodiments, a “safe” condition can only be indicated when derrick man  106  is at least in proximity to the safety cable  600  of connecting device  602 . 
         [0032]    In some embodiments and referring to  FIGS. 7 ,  8  and  9 , derrick man  106  is located on an oil drilling rig  200 . Drilling rig  200  works on a drill pipe stand  202  that has a finger board  204  that keeps drill pipe stands  202  separated. Drill pipe stand  202  also has a racking board  214  that is used to rack stands of drill pipe when worker  106  is making a trip to change a drill bit or to install a different drilling tool. The racking board is usually about 24 to 30 meters above the floor, as indicated by bracket  206 . On most drilling rigs  200 , derrick man  106  climbs up a ladder  208  to reach racking board  214  to enter an open or “working” side  212  of derrick  200 . A traveling block  210  is used to pull pipe out of a well and return it to the floor of drilling rig  200 . 
         [0033]    Derrick man  106  works on racking board  214  when the rig is “tripping” pipe into or out of a well. He is constantly walking from the outside or back of racking board  214  to the open or working side  212  of derrick  200 . In some embodiments, a block  216  (such as a DBI/SALA® brand fall protection device, available from D B Industries, Inc., Red Wing, Minn.) is used to provide a measure of protection for derrick man  106  when he is climbing derrick  200 . Once at racking board  214 , derrick man  106  transfers himself to another block (not shown in the Figures) attached to the top of derrick  200 . 
         [0034]    Once derrick man  106  is in position, he engages switch  10  (not shown in  FIG. 7 ,  8  or  9 ), which is wired to a light panel  220  below in driller's shelter  218 . This engagement completes an electrical circuit that provides a visual indication on light panel  220  to the driller that derrick man  106  has attached the appropriate block  216  to his harness and is ready to resume operations. 
         [0035]    Sometimes due to a stop in running the pipe, derrick man  106  may unhook or sit and wait for operations to resume. With switch  10  disengaged, the driller knows not to raise the traveling block  216  (lifting or lowering the drill string) until derrick man  106  confirms through light panel  220  that he is hooked up to his fall protection. In some embodiments, switch  10  can also (or alternately) be used to signal equipment for automatic cut-off. Also, in some embodiments, an alarm or light remains actuated until switch  10  is reengaged. 
         [0036]    In some embodiments of the present invention, a horn (not shown in the drawings) is provided in addition to light panel  220 , and engagement of switch  10  also (at least momentarily) sounds the horn as a signal to the driller. 
         [0037]    In some embodiments of the invention, switch  10  is designed for rugged conditions, and is shock-resistant, water-tight, and/or corrosion resistant. For example, the cylindrical metallic parts of switch  10  may comprise anodized aluminum, and rubber O-rings  58  and  60  provide a water-tight seal. 
         [0038]    In some embodiments of the invention, switch  10  comprises a two-piece unit having a plunger  12  and a receptacle  14 . Receptacle  14  is attached to rig  200  at an appropriate location and plunger  12  is attached to derrick man  106 . When plunger  12  and receptacle  14  are joined together, a switch is tripped and a circuit is completed. The signal generated by the completed circuit is used to alert the driller that derrick man  106  is properly harnessed and prepared to begin rig operations. 
         [0039]    In some embodiments, receptacle  14  and plunger  12  are held together by friction. When plunger  12  is properly inserted into receptacle  14 , an electrical contact is made within switch  10  and a circuit completed. Plunger  12  and receptacle  14  are each anchored to its respective piece of the safety harness system with enough lead to permit plunger  12  and receptacle  14  to be joined together only when the safety equipment is properly in place. In one embodiment, the completed circuit (or a relay or electronic switch controlled thereby) turns a red light on light panel  220  to green, thereby letting the driller know that the derrick man is ready for operations. If the derrick man removes his safety harness, plunger  12  is necessarily removed from receptacle  14 , breaking the circuit and changing the green light to red. 
         [0040]    In some embodiments of the present invention and referring to the block schematic drawing of safety system  400  of  FIG. 10 , various crew members  402  are required to be in different locations around rig  200 . In these embodiments, proximity technology is combined with switch  10  to relay information to driller  408  regarding the location of each crew member  402 , which may also include derrick man  106 . When the responsible crew member  402  is where he or she is supposed to be for the operation being undertaken, driller  408  is notified by a signal, such as a red light  410  turning green on panel  220 . Only when all lights  410  are green would the driller  408  begin rig operations. 
         [0041]    For example, and referring to  FIGS. 6 and 10 , a radio frequency identification (RFID) tag  302  is assigned to each crew member  402  (which may, but need not necessarily include derrick man  106 ). RFID technology is suitable for this purpose because it can be used in harsh environments and tuned for distance. Either active or passive RFID tags  302  are suitable. The use of RFID tags  302  permits data acquired to be passed to databases  416  that can record histories and/or determine safe or unsafe conditions by comparing the location of each crew member  402  to a database of predetermined locations. The predetermined conditions can be modified to take account of rig configuration, size of crew, operation being undertaken, individual company safety policies, and/or any other factors as may be appropriate. 
         [0042]    RFID tag  302  is, in some embodiments, embedded in a hard hat  300 . In other embodiments, RFID tag  302  is embedded in another device associated with an individual crew member  402 . For example, RFID  302  may be worn inside clothing like “dog tags” or incorporated into other safety gear. Sensors  404  with wireless antennae  406  are located around rig  200  can constantly track and report the location of each RFID  302  signal associated with a crew member  402 , and each RFID  302  may be separately identified with an individual crew member  402 . Data from sensors  404  are transmitted via antennae  406  to a receiver comprising an antenna  412  and a modem  414 . Data from modem  414  is fed to control panel  220  either directly or indirectly, where it is used by driller  408  to determine the location of the crew members  402 . Control panel  220 , for example, may display a light  410  when a crew member  402  is present at his assigned location, or additional electronic control logic and/or databases  416  can be provided in or associated with control panel  220  to compare the crew members  402  present and their locations with a predetermined set of parameters to advise driller  408  whether the needed personnel were present and in the location in which they were supposed to be for the operation being undertaken. In some embodiments of the present invention, derrick man  106  uses an RFID tag  302  either to supplement or to substitute for switch  10 , although in most embodiments, it is envisioned that derrick man  106  would use switch  10  and no RFID tag, at least in part because of his location. 
         [0043]    It will be appreciated that some configurations of the present invention provide a comprehensive approach to monitoring crew behavior and location. It will also be appreciated that some configurations of the present invention provide apparatus to make drilling operations safer, and/or that assist in changing the behavior of personnel to make safety systems more effective. 
         [0044]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.