Abstract:
An improved bypass device for a fall arrest system that is not impeded by cable supports as it is pulled along a flexible and/or rigid cable. The bypass device has a gate which can be quickly and easily removed from a frame of the bypass device to reveal an opening which allows the bypass device to be positioned on the cable. Once the bypass device is positioned on the cable, the gate may be reattached to the frame to partially close the opening. A portion of the opening remains unblocked by the gate so that the bypass device will pass over one or more cable supports when it is pulled along the cable. The cable supports act to guide the cable along a desired workpath. The supports are also constructed to withstand the force exerted on the cable in the event someone or something connected to the bypass device falls.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates generally to a safety apparatus which moves along a cable and serves as a support for a safety line or the like, and more particularly, to an improved fall arrest bypass device which may ride freely on a flexible and/or rigid cable without being impeded by cable supports intervally located along the cable. 
     Workers who perform tasks at heights on elevated or suspended platforms, and workers who operate near vertical edges need to be protected from falls that could cause injury or death. In fact, the U.S. government has established the Occupational Safety and Health Administration (“OSHA”) to regulate employers having workers who perform job tasks in these types of environments. Under regulations enacted by OSHA, each employee must be protected by a safety system when walking or working on a surface higher than six feet above the ground or a lower level. 
     This safety system may be a fall arrest system which arrests an employee in a short distance following a fall from a working level. A conventional fall arrest system consists of an anchorage point, a harness, and a mechanism connecting the harness to the anchorage point. It may also include a lanyard, deceleration device, lifeline, or suitable combination of these elements. A personal fall arrest system must limit the maximum arresting force on an employee to 1800 pounds, and be rigged so that an employee cannot fall more than six feet or come in to contact with any lower level. The fall arrest system must also be constructed to have sufficient strength to withstand twice the potential impact energy of a free-fall of six feet or the stopping distance provided by the system, whichever is less. 
     Fall arrest systems which are presently in use are typically attached to a single fixed anchor point. A worker is connected to the fixed anchor point by a lanyard attached to a harness or safety belt worn by the worker. This single fixed anchor system is a safe option for performing tasks in a limited area, but many tasks require the worker to move over a larger area. In the latter situation, the worker must disconnect the lanyard from the fixed anchor point and reconnect it to another fixed anchor point. During the change-over time, the worker is in danger of falling, which could result in serious injury or death. As a result, the single fixed anchor point system severely limits the type of tasks a worker can safely and legally perform. 
     Other safety systems exist that provide more mobility than the single fixed anchor point system. For example, in a track system, a lanyard is attached at one end to the worker via a harness, and to a trolley, slide, or other movable component on the other end. The trolley, slide, or other movable component is adapted to move freely along a conventional track, which can be an I-beam, a metal or plastic rail, or a cable that is either supported at various points along a work path or is anchored safely at its two end points. The supports function to both hold the track in place and to support the weight of the trolley and one or more workers in the event of a fall. The track is usually directly overhead in relation to the worker&#39;s position, and can curve around corners or incline at angles. Some tracks such as I-beams require permanent installation. 
     Tracks like that described above typically require numerous supports which present an obstacle to conventional track-type fall arrest devices. A worker using a conventional fall arrest device must disconnect the device from the track between each support. Again, this places the worker in danger of falling. Additionally, these devices create wear on the track as well as the fall arrest device itself, which may result in frequent and costly replacement of parts. 
     Many tasks could be made easier and would benefit from a hands free fall arrest device that can pass freely over or through the track supports unaided by human intervention and unimpeded by undue frictional orientation of passing components. Designs of track-traveling and fall arrest devices that permit movement of a device past a plurality of local track supports are known. U.S. Pat. No. 304,730, to High, describes a truck that rides upon a gas-pipe track to move a fire escape ladder around a building. The truck disclosed by the High patent has two independent yokes, each with a carrying wheel adapted for the track. A gate is located on the rear side of the truck, and is hinged to the truck with a fulcrum-pin to allow the truck to pass through brackets that support the track. The truck described by the High patent is bulky and heavy, which prevents its use as a fall arrest device. Furthermore, these types of trucks are expensive to manufacture due to the redundant components that may be necessary to support an off-balance fire escape ladder, but are not necessary to support workers or other objects. 
     U.S. Pat. No. 5,979,599, to Noles, describes another track-traveling apparatus that rides upon a cable safety track which is supported by a plurality of supports. Noles discloses a track-traveling element with a single pulley that can ride upon the cable safety track. The track-traveling element has a slot which allows the element to pass over the brackets which support the cable. However, the track-traveling element disclosed by Noles cannot be removed from the cable safety track without severing the track or disengaging the track from its source. The permanence of the track-traveling element will cause it to be exposed to environmental conditions that could cause wear and corrosion, and prevents the track-traveling element from being easily removed and stored for later use. 
     To overcome the problems and disadvantages associated with the prior art, it is an objective of the improved bypass device of the present invention that it be strong enough to withstand the force of a falling object connected to the device. Furthermore, the bypass device should also be attached to a cable in a manner sufficient to hold a worker in case of a fall. 
     It is another objective that the improved bypass device of the present invention be capable of riding freely along a cable and passing over one or more support brackets without having to be removed from the track. The bypass device should also be able to ride freely around corners and curves of the track without having to be removed. 
     It is a further objective that the improved bypass device of the present invention be securely attached to the cable to prevent accidental disengagement that would place the worker in a dangerous situation. However, the improved bypass device of the present invention should also have a mechanism to easily remove it from the track so that the bypass device may be stored when not in use. 
     Another objective of the bypass device of the present invention is that it be lightweight with easily replaceable parts, and that it can be adapted to fit different size cables. The bypass device should ride freely on the cable without encountering significant friction, thereby preventing wear on the bypass device itself, as well as preventing the bypass device from causing any degree of wear to the support cable. 
     Finally, it is also an objective of the improved bypass device of the present invention that all of the aforesaid advantages and objectives be achieved without incurring any substantial relative disadvantage. 
     SUMMARY OF THE INVENTION 
     The disadvantages and limitations of the background art discussed above are overcome by the improved fall arrest bypass device which is taught by the present invention. 
     The bypass device is a component of a safety system which will meet and exceed applicable standards the government (OSHA) requires to protect workers having job duties at hazardous heights. The bypass device is attached at one end to a cable, and at the other end to a safety line extending to a harness of a worker. The safety line can be a rope lanyard, a retractable cable, webbing, or other types of lines known by those skilled in the art. The cable is engineered to support one or more workers in the event of a fall, and can be made from steel, nylon, polyester, or other well-known materials. 
     The cable should be held by supports located approximately every 20 feet to about 200 feet along the length of the cable, depending on the ground clearance and the flexibility of the cable used. The supports can hold the cable in a straight line, or, alternatively, the supports can be curved to wrap the cable around corners and over ledges. Each support may be mounted to the exterior of a building or rooftop along the work path, or, alternatively, the supports can be mounted upon poles along the work path. The supports are typically mounted by a mechanical securing device such as a bolt or other threaded fastener, or attached or mounted in other well-known ways including welding so that the supports can withstand the force exerted on the cable in the event one or more workers fall. 
     The bypass device connects the worker to the cable and is pulled along the cable and over the supports as the worker travels along the work path. The bypass device includes a frame member with a C-shaped body with two legs and an arm that extends downwardly from the base of the C-shaped body. The two legs surround a pulley located in a space therebetween. The pulley is grooved to fit in a mating relationship with the cable, and the pulley rotates around a pulley shaft with the assistance of a bearing so that it rides on the cable and over the supports with little friction. It would be apparent to one of skill in the art that the size and shape of the pulley will vary depending on the size of the cable and supports. 
     To attach the bypass device to the cable, the worker passes the cable through an opening to the interior space of the C-shaped body of the frame member. The opening is greater. than the cross-sectional diameter of the cable or section of the support holding the cable so as to allow the bypass device to pass onto the cable and support. Additionally, the opening permits the bypass device to pass over and through the supports when pulled along the cable. 
     To ensure that the bypass device remains engaged to the cable during use, a removable entry gate is attached to the frame member proximate the opening. The removable entry gate can either be attached to the arm of the frame member below the opening, or to one of the legs of the C-shaped body superior the opening. The gate reduces the size of the opening but does not close the opening completely. As a result, the opening is. made smaller than the cross-sectional diameter of the cable and supports and will prevent accidental disengagement during use. However, the partial opening is wide enough to allow a worker to pull the bypass device over the supports without having to detach the bypass device at each support. 
     The removable entry gate can be in a variety of shapes and sizes. For example, in one embodiment of the present invention, the removable entry gate is a single, substantially rectangular gate that partially blocks the opening to the interior of the body. Another embodiment may include two separate removable entry gates, each of which partially block the opening to ensure that the bypass device does not become disengaged from the cable. Because one of the purposes of the removable entry gate is to ensure that the bypass device remains engaged with the cable or supports, while allowing the bypass device to pass over the supports, one skilled in the art would realize that any imaginable embodiment of such a gate will fall within the scope of the present invention. 
     Once the removable entry gate is attached to the frame member, the worker is secured to the cable by the safety line attached to the arm of the frame member. The safety line may be attached to the arm directly by a latch, lockable D-ring, snap lock, or carabiner, or it may also be attached to a connector independently attached to the arm. The connector can be either a ring or swivel with a ring for attachment to the safety line. A swivel may allow for more mobility and a greater range of motion, however, it is not necessary for operation and use of the present invention. 
     Thus, it may be seen that the improved bypass device of the present invention overcomes the problems and disadvantages associated with the prior art by providing the aforesaid characteristics. The improved bypass device is strong enough to withstand the force of a falling object attached to the bypass device. Furthermore, the bypass device is removably attachable to a cable in a manner sufficient to hold a worker in case of a fall. The improved bypass device of the present invention also rides freely along a cable and can pass over support brackets, straight or curved, without having to be removed from the cable. 
     Furthermore, the improved bypass device of the present invention will remain engaged with the cable by its innovative use of a removable entry gate that prevents the bypass device from becoming disengaged from the cable, which would prevent a worker from being placed in a dangerous situation. This removable entry gate can also be easily removed so that the bypass device can be stored when not in use. 
     The bypass device of the present invention is also lightweight, with easily replaceable parts that can be adapted to fit cables of different size. The pulley of the bypass device allows the bypass device to ride freely on the cable without significant friction to prevent wear on the bypass device itself and prevent the bypass device from causing the cable to wear. 
     Finally, all of the aforesaid advantages and objectives are achieved without incurring any substantial relative disadvantage. 
     The above brief description sets forth rather broadly the more important features of the present invention so that the detailed description that follows may be better understood, and so that the present contributions to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter, which will form the subject matter of the invention. In this respect, before explaining an embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements set forth in the following description or illustrated in the drawings. The present invention is capable of other embodiments and of being practiced and carried out in various ways, as will be appreciated by those skilled in the art. Also, it is to be understood that the phraseology and terminology employed herein are for description and not limitation. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     These and other advantages of the present invention are best understood with reference to the drawings, in which: 
     FIG. 1 is an isometric view of a bypass device and a support which are constructed in accordance with the preferred embodiment of the present invention; 
     FIG. 2 is a front elevation view of the bypass device shown in FIG. 1; 
     FIG. 3 is a side elevation view of the bypass device and the single support as illustrated in FIG. 1; 
     FIG. 4 is an isometric front view of the bypass device shown in FIG. 1 from a lower angle; 
     FIG. 5 is a side elevation view of the bypass device shown in FIG. 1 without a pulley; 
     FIG. 6 is a side elevation view of the removable entry gate shown in FIG. 1; 
     FIG. 7 is a front elevation view of the removable entry gate illustrated in FIG. 1; 
     FIG. 8 is a front elevation view of the bypass device shown in FIG. 1 with an alternative removable entry gate which is constructed in accordance with the teachings of the present invention; 
     FIG. 9 is a front elevation view of the bypass device shown in FIG. 1 with two removable entry gates which is constructed in accordance with the teachings of the present invention; 
     FIG. 10 is a side elevation view of a pulley of the bypass device as shown in FIG. 1; 
     FIG. 11 is a front elevation view of the pulley of the bypass device shown in FIG. 10; and 
     FIG. 12 is an isometric view of a worker using the bypass device of FIGS. 1-4 in combination with a cable supported by a plurality of supports in accordance with the teachings of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings, and more particularly to FIG. 1 which illustrates a bypass device  20  of the present invention as used in combination with a cable  42  and a support  40 . As is shown, the bypass device  20  travels along the cable  42  and passes over a guiding segment  44  of the support  40 . Each of these features and the manner in which they are interrelated will be discussed in detail below. 
     FIGS. 1 and 3 illustrate a support  40  that holds a portion of a cable  42  along a desired work path for use in combination with a bypass device  20  of the present invention. The support  40  includes a base  46 , an extension  48 , and a guiding segment  44 . The base  46  is shown as a parallelogram, but can be most any shape. The base  46  is the portion of the support  40  that is mounted to the exterior of a building or along a rooftop by conventional mounting methods including a mechanical securing device such as a threaded fastener or bolt, or by more permanent methods including welding. Alternatively, the base  46  of the support  40  may be mounted to a secured pole or mounting bracket. 
     The extension  48  projects outwardly from the base  46  at an angle substantially normal to the base  46  and can either be forged, molded, welded or joined to the base  46  by other less permanent methods including threaded fasteners or coupling devices. To further secure the extension  48  to the base  46 , a fin  47  may also be used and can be joined to the base  46  and the extension  48  by similar methods. The guiding segment  44  is positioned at the terminal edge  47  of the of the extension  48 . In one embodiment, the guiding segment  44  is a hollow cylindrical segment that extends along the terminal edge  49  of the extension  48 . The hollow cylindrical segment has a diameter larger than the cross-sectional diameter of the cable  42 , so that a portion of the cable  42  may pass therethrough as shown in FIG.  3 . To ensure that the guiding segment  44  is sufficiently strong to withstand the force of a falling worker, the guiding segment  44  is either forged or welded to the extension  48 . 
     All portions of the support  40  may be constructed from suitable materials such as 6061 aircraft aluminum, stainless steel, ceramic materials, and plastic materials. Additionally, other embodiments of the support  40  may have a guiding support  44  that is not a hollow cylindrical segment, but is in the shape of a “C” or “U” to support and guide the cable  42 . Furthermore, it would be apparent to those skilled in the art to use alternative cable supports that can be used in conjunction with the bypass device  20  taught by the present invention. 
     One cable  42  that may be used in combination with the bypass device of the present invention is a {fraction (5/8″)} diameter polyester fiber cable manufactured by Wall Industries, Inc., U.S.A. and sold under the PERMACABLE trademark by Sellstrom Manufacturing Company, U.S.A. A portion of the cable  42  passes through the hollow cylindrical segment  44  to prevent sagging in the cable  42 , and to provide sufficient tension to hold a worker in the event a worker falls. Although the cable described above is one available cable, other types of cables may be used in combination with the bypass device  20  including cables made from polysteel, steel, KEVLAR by DuPont, U.S.A., or other synthetic materials. 
     FIGS. 1-4 depict one embodiment of a bypass device  20  constructed in accordance with the present invention. The bypass device  20  includes a frame member  22  with a body  24  and an arm  30 . The body  24  is formed in a shape similar to an upper case letter “C, ” as shown in FIG. 5, although the shape of the body  24  may vary. FIGS. 1-5 illustrate a body  24  of the frame member  22  with two legs  26  and  28  that may be substantially parallel. The arm  30  extends downward from the base of the C-shaped body  24 . The legs  26  and  28  are separated by a distance to create a space  27  therebetween to house a pulley  60  shown in FIGS. 1-4. One leg  26  of the C-shaped body  24  can be continuous with the downward extending arm  30 . The other leg  28  of the C-shaped body  24  is suspended over the downward extending arm  30  to create an opening  32  to the space  27  between the legs  26  and  28  of the C-shaped body  24 . 
     The frame member  22  can be made from a suitable material such as 6061 aircraft aluminum. However, other embodiments constructed in accordance with the present invention may utilize other materials known to those of skill in the art including stainless steel, ceramic materials, and plastic materials. Additionally, the frame member  22  can be made from a single piece of material, or may be constructed from multiple pieces of the same material, or from multiple pieces of different types of materials, as would be apparent to one skilled in the art. 
     Referring to FIG. 3, the opening  32  to the space  27  between the legs  26  and  28  of the C-shaped body  24  is wider than the cross-sectional area of the cable  42  or the guiding segment  44  to permit the worker to place the bypass device  20  onto the cable  42 . Because different cables and supports may be used, the width of the opening  32  will vary depending on the size and shape of the cable  42  and supports  40  as they are used in combination with the bypass device  30 . 
     Once the bypass device  20  is positioned on the cable  42  or the guiding segment  44  as shown in FIGS. 1-4, the bypass device  20  may be removably engaged with the cable  42  by a. removable entry gate  50 . The entry gate  50  can be attached to the frame member  22  proximate the opening  32  by at least one removable fastener  52  such as a bolt or a detent pin as shown in FIGS. 2 and 4, respectively. Other types of removable fasteners may also be used including bendable and non-bendable cotter pins or other removable fasteners  52  known by those skilled in the art. 
     In one embodiment, the removable entry gate  50  is attached to the downward extending arm  30  beneath the opening  32 . However, other embodiments of the present invention locate the removable entry gate  50  on the leg  28  superior the opening  32 . Once attached, the entry gate  50  partially blocks the opening  32 , thereby reducing the width of the opening  32  to a size smaller than the cross-sectional area of the cable  42  or guiding segment  44 . This ensures that the bypass device  20  will remain engaged to the cable during use, and also allows the bypass device  20  to pass through the supports  40  without having to be removed. 
     One embodiment of the removable entry gate  50  is more clearly shown in FIGS. 6 and 7. The removable fasteners  52  shown in FIGS. 2 and 4 are inserted in one or more attachment holes  54  and then pass into one or more mating holes  51  tapped or bored into the arm  30  of the frame member  22  as shown in FIG.  1 . FIG. 7 also illustrates one embodiment of the removable entry gate  50  as being substantially rectangular with a beveled top portion  58  and bottom portion  59  to provide a greater range of motion for the bypass device  20  as it used in combination with the cable  52  and supports  40 . However, other embodiments of the present invention may have one or more removable entry gates of varying size and shape for the purpose of preventing disengagement of the bypass device  20  from the cable  42 . 
     For example, FIG. 8 illustrates a bypass device  20  with a single entry gate  150  with a width less than the width of the arm  30 . FIG. 9 shows another embodiment of the present invention with two removable entry gates  152  that are removably attached to the arm  30 . From these examples, it would be readily apparent to one skilled in the art to use one or more entry gates which may be in a variety of shapes and sizes so long as the gate(s) reduces the size of the opening  32  to prevent the bypass device  20  from disengaging with the cable  42  or a portion of the supports. 
     When the worker places the bypass device  20  onto the cable  42  or hollow cylindrical segment  44 , the pulley  60  bears the weight of the bypass device  20  and the attached worker as is shown in FIGS. 1-4. The pulley  60  is positioned within the space of the frame member  22  between the two legs  26  and  28  of the C-shaped body  24 , and is mounted to the frame member  22  by a pulley shaft  62  extending through the legs  26  and  28  and the pulley  60 . The pulley shaft  62  may be a bolt or rod with end caps to prevent the pulley shaft  62  from coming loose. 
     The pulley  60  is more clearly displayed in FIGS. 10 and 11. FIG. 11 shows a center hole  64  with a bearing or bushing  66  that is coaxially located therein to allow the pulley  60  to rotate freely around the pulley shaft  62 , thereby reducing friction when the bypass device  20  is pulled along the cable  42  and over the hollow cylindrical segments  44 . The pulley  60  engages the cable  42  and hollow cylindrical segment  44  at a groove  68  machined into the radial edge of the pulley  60 . Like the frame member  22 , the pulley  60  can be made from aluminum, stainless steel, plastic or other materials known by those skilled in the art, and it can vary in size depending on the diameter or shape of the cable  42  and supports  40 . Furthermore, the radius or depth of the groove  68  may also vary in size to fit the cross-sectional area of the cable  42  or hollow cylindrical segment  44 . 
     FIG. 12 illustrates a worker  70  using the bypass device  20  in combination with the cable  42  and a plurality of supports  40 . As the worker  70  travels along the work path, the worker  70  pulls the bypass device  20  along the cable  42  and over each support  40 . The cable  42  is held along a work path by a plurality of supports  40  mounted to a larger structure. The number of supports  40  can vary depending on the flexibility and type of cable used in the safety system. 
     The worker  70  is connected to the cable  42  by a safety line  72  that is rated for a fall arrest system. Often times, the safety line  72  is expandable or includes a separate shock absorbing mechanism (not shown). The safety line  72  can be connected to the downward extending arm  30  of the frame member  22  either directly by a clip  74  attached to the safety line  72  as shown in FIG. 2, or it can be indirectly attached to the bypass device  20  by a connector  76  as shown in FIGS. 1-4. Methods of connecting the safety line  72  to the bypass device  20  are well-known by those skilled in the art and can include the use of lockable dee-rings, snap hooks, and carabiners. These same devices can also be used as connectors. However, in one embodiment of the present invention, the connector  76  is a swivel that is rated to hold 13600 pounds as is shown in FIG.  4 . The swivel connector allows the worker to move and rotate freely without twisting the safety line. 
     The advantages of the disclosed invention are thus attained in an economical, practical and facile manner. While preferred embodiments and example configurations have been shown and described, it is to be understood that various further modifications and additional configurations are apparent to those skilled in the art. It is intended that the specific embodiments and configurations herein disclosed are illustrative of the preferred and best modes for practicing the invention, and should not be interpreted as limitations on the scope of the invention as defined by the appended claims.