Abstract:
A retractable lifeline comprises a housing a drum rotationally mounted in said space and a lanyard wound about said drum. The lanyard extends from the housing and is extendable from said housing and retractable into said housing. The retractable lifeline further includes a lock assembly to prevent rotation of said drum, and hence extension or retraction of said lanyard, when said lanyard is at a desired length, and an override of the lock mechanism in case of a fall so that the retractable internal shock absorption and clutch mechanism can arrest the fall.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Provisional Application No. 61/199,122 filed Nov. 13, 2008 and which is incorporated herein by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    This application discloses a cable reel lock for a fall arrestor which enables workers doing leading edge work on elevated structures to secure their location at fixed distances from their anchorage and still be provided with energy absorbing fall arrest protection, as well as a method of using the cable reel lock. 
         [0004]    Fall protection anchorage devices are used for worker safety in many industrial applications to provide fall protection for workers working at heights. There are generally two types of fall protection anchorage devices, both of which attach to the dorsal D-ring of a worker&#39;s harness. The first type of device is a sewn webbing lanyard that uses (tear-away) webbing that rips apart during a fall arrest to provide the worker with a “soft stop” by limiting the fall arrest forces to no more than 900 lbs (4000 N) and the deceleration distance to no more than 42″ (˜1 m). These devices are generally less expensive but limit the worker&#39;s mobility to no more than 6 ft (˜1.8 m) from his anchor point 
         [0005]    The second type of anchorage device used for fail arrest is referred to as a retractable lifeline. These devices are comprised of a drum reel containing lanyard which can be made from wire cable or rope, synthetic cable or rope, or synthetic webbing. These devices normally are produced in sizes that range from 6 ft to 120 ft (˜1.8 m to ˜36.6 m). For this reason they provide the worker with a much greater range of mobility. 
         [0006]    While most fall arrest anchorage devices are physically located above the worker&#39;s work area and provide for fall arrest in a vertical fall, retractable lifelines enable a worker, when working on a horizontal surface such as a rooftop, to reach the roof edge. Should the worker fall at this position the lanyard (whether steel cable or webbing) will be pulled across the roof edge causing it to not only bend sharply but be subjected to sharp cutting edges while under fall arrest loading. Testing in the United States and Europe has shown that many commonly used roof edges will cut, fray, or significantly weaken the retractable lanyard sufficiently to make it unsafe for fall arrest use. 
         [0007]    To address this problem, a new line of “leading edge” retractable lifelines have been designed and tested for use in these applications. Most significantly, testing has shown that the lanyards used in these devices must be increased about 30% in diameter to carry the intended loads. Secondly, a lock mechanism has been added to the cable reel to enable the worker to limit the cable extraction at any location to prevent him from reaching the leading edge. By locking the cable at any length from his anchorage the worker can use the cable as a work-positioning device preventing him from overreaching the leading edge thus preventing the onset of a fall. This lock device, however, must not prevent the shock absorber in the retractable from working in case of an accidental fall. For this reason the lock mechanism must be able to be unlocked manually by the worker and yet it must be overridden automatically in case a fall occurs. The following description provides details of preferred embodiments of such an invention. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    An improved retractable lifeline is disclosed for use as a leading edge retractable lifeline that will enable a worker to use a retractable lifeline as a travel restriction device without overriding the internal shock absorption available in a retractable lifeline. The retractable lifeline allows the worker to manually lock the retractable reel of the retractable lifeline at any location that will provide the correct lanyard length to keep the worker from overreaching his workspace leading edge, thus creating the potential for an accidental fall. 
         [0009]    Briefly stated, the retractable lifeline comprises a housing having a front portion and a back portion; each the portion comprising a surface and a wall. The front and back portions define a hollow space when joined together and an exit from the hollow space. A drum is rotationally mounted inside the housing and a lanyard is wound about the drum. The lanyard can be extracted from the housing to lengthen the exposed portion of the lanyard and retracted into the housing. 
         [0010]    The retractable lifeline further includes a locking assembly which is selectively movable between a locked position and an unlocked position. In the locked position, the drum cannot rotate, and hence the lanyard can not be extended from, or retracted into, the housing. In the unlocked position, the drum is free to rotate, and hence, the lanyard can be both extended from and retracted into the housing. The lifeline further includes a release which will automatically release the lifeline from the locked position to allow the drum to rotate when more than a determined amount of force is applied to the lanyard. 
         [0011]    The locking assembly comprises a ring gear rotationally fixed to the drum, a pinion gear mounted in the housing, and a shaft to which one of the ring gear and pinion gear are rotationally fixed. The shaft is selectively movable axially between a first locked position in which the ring gear and the pinion gear are engaged and a second unlocked position in which the ring gear and pinion gear are not engaged. The locking assembly further includes a mechanism for prevention rotation of the shaft at least when the shaft is in the first locked position to prevent rotation of the drum when the locking assembly is in the locked position. 
         [0012]    The mechanism for preventing rotation of the shaft (and hence of the drum) comprises a protrusion extending from the shaft which engages the housing to prevent rotation of the shaft relative to the housing at least when the shaft is in the first locking position. However, the protrusion automatically disengages the housing when more than a predetermined amount of force is applied to the lanyard to allow the drum to rotate. In an illustrative example, the protrusion comprises a shear pin which extends from the shaft. In this example, the housing includes at least a lock slot which receives the shear pin. When the shear pin is engaged in the slot retaining the shaft in the first locked position; the shear pin being sized and shaped to break when more than the predetermined force is applied to the lanyard. In a preferred embodiment, the housing comprises two intersecting slots, the slots being of different depths, whereby when the shear pin is in one slot, the shaft is in the first locking position and when the shear pin is in the second slot, the shaft is in the second unlocked position. The two slots can, for example, be formed on a boss extending from the housing surface. 
         [0013]    The retractable lifeline allows the worker to unlock, reposition, and re-lock the cable reel at any desired location. Further, the lifeline provides for an override of the lock mechanism in case of a fall so that the retractable internal shock absorption and clutch mechanism can arrest the fall. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a leading edge retractable lifeline; 
           [0015]      FIGS. 2A-C  are plan, cross-sectional and perspective views, respectively, (with the housing back portion, drum and lanyard omitted from  FIG. 2C  for purposes of illustration) showing retractable lifeline device in a locked position to prevent extension and retraction of the lifeline lanyard; 
           [0016]      FIGS. 3A-C  are plan, cross-sectional and perspective view, respectively, (with the housing back portion, drum and lanyard omitted for purposes of illustration) showing retractable lifeline device in an unlocked position to allow for extension and retraction of the lifeline lanyard with the drum and ; 
           [0017]      FIG. 4  is a detail of drum and pinion gears showing the gears in an engaged position; 
           [0018]      FIG. 5  is a detail of the weld boss showing the different lock groove depths for holding the shear pin; 
           [0019]      FIG. 6  is a detail of the pinion and reel gears showing the engagement spring that hold the gears in engagement; 
           [0020]      FIG. 7  shows a detail of the handle assembly with the shear pin and engagement spring; 
           [0021]      FIGS. 8A and 8B  are cross-sectional views of the retractable life line in locked and unlocked positions, respectively, with an alternative handle assembly; and 
           [0022]      FIGS. 9A and 9B  are enlarged cross-sectional views of the handle assemblies of the lifelines of  FIGS. 8A and 8B , respectively. 
       
    
    
       [0023]    Corresponding reference numerals will be used throughout the several figures of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    The following detailed description illustrates the claimed invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the claimed invention, and describes several embodiments, adaptations, variations, alternatives and uses of the claimed invention, including what we presently believe is the best mode of carrying out the invention. Additionally, it is to be understood that the claimed invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The claimed invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
         [0025]    A retractable lifeline device  10  is shown generally in  FIG. 1  and in more detail in  FIGS. 2-7 . The retractable lifeline device  10  comprises a housing  12  comprised of a front portion  12   a  and a back portion  12   b.  As seen, the housing is generally tear- or pear-shaped. The front and back portions each have wall surfaces  14  and walls  16 . When the front and back portions are joined together, the surfaces  14  and walls  16  of the front and back portions define a hollow space in which a drum  18  is rotatably mounted. The drum, for example, can be mounted about an axle  20  which extends between the front and back portions. Bearings  22  can be positioned between the drum and the axle to facilitate rotation of the drum about the axle. A lanyard  24  is wound about the drum. As is known, the lanyard extends through an exit  26  in the bottom of the housing  12 . A clip  27  is mounted to the end of the lanyard to allow the lanyard to be connected to the D-ring of worker&#39;s harness. As is standard, a spring element (not shown) is provided so that the drum will automatically rotate when tension on the lanyard is reduced to retract the lanyard into the housing and about the drum. 
         [0026]    A boss  30  extends form the surface  14  of the housing front portion  12   a  near the bottom of the housing  12 . The boss  30 , as seen best in  FIG. 5 , comprises two intersecting slots  32  and  34  with a circular hole  36  at the intersection of the two slots. The first slot  32  is shallower than the second slot  34  and includes a floor  32   a . The second slot  34  and the hole  36  are both shown to extend through the boss  30 . 
         [0027]    A handle  40  (shown in FIGS.  1  and  6 - 7  as T-handle) comprises a grip  42  which is connected to a shaft  44 . The shaft  44  is sized to pass through, and rotate in, the hole  36  of the boss  30 . A shear pin  46  extends through the shaft  44  and is generally perpendicular to the shaft  44 . The shear pin  46  has a length greater than the diameter of the boss hole  36 , but less than the length of the boss slots  32 ,  34 , such that the pin can be received in the slots. The shear pin is designed to shear when rotational or other shear forces greater than 400 lbs (˜1780 N) are applied to the pin. 
         [0028]    Internally of the housing  12 , the retractable lifeline  10  comprises a ring gear  50  fixed (or operatively fixed) to the drum to rotate with the drum  18 . Additionally, a locking gear  52  (such as a pinion gear) is rotationally fixed to the end of the handle shaft  44 . A pin  54  can extend through the body of the pinion gear  52  and the shaft  44  to rotationally fix the pinion gear  52  to the shaft  44 . The ring gear  50  and the drum are positionally or axially fixed relative to the housing. However, the handle  40 , and hence the pinion gear  52  can translate axially relative to the housing. Hence, the pinion gear  52  can be moved into and out of engagement with the ring gear  50 . 
         [0029]    When the shear pin  46  of the handle shaft  44  is received in the shallower slot  32 , the pinion gear  52  will be in engagement with the drum gear  50 , as seen in  FIG. 2B . In this position, the engagement of the pinion gear with the drum gear will prevent the drum from rotating, and the lanyard will be fixed at a determined length—that is, with the pinion and drum gears engaged, the drum will not be able to rotate about the axle  20  and the lanyard  24  will not be able to be extended or retracted. However, when the handle  40  is rotated so that the shear pin  46  is received in the deeper slot  34 , the pinion gear  52  will be out of engagement with the drum gear  50 , as seen in  FIG. 3B . In this unlocked position, the drum  18  is free to rotate about the axle  20 , and hence, the lanyard  24  can be extended and retracted as a worker moves about. A biasing element  56  is positioned between an inner surface of the boss  30  and the pinion gear  52  to urge the pinion gear inwardly relative to the housing. The biasing element  56  comprises a coil spring which, as shown, can extend into a cavity in the boss  30 . The end of the spring opposite the pinion gear can engage a surface of the boss, such as a surface opposite the floor  32   a  of the slot  32 . Alternatively, the end of the spring could bear against an inner surface of the housing front portion  14 . 
         [0030]    Under normal operation the handle  40  is positioned with the shear pin in the unlocked slot  34  so that the retractable lifeline device  10  is allowed to extend and retract the cable lanyard as the worker moves about the work area. When the worker reaches a leading edge that poses a fall hazard, the worker has the option to engage the reel lock which will cause the unit to function as a travel restrictor. It also enables him to lean against the cable if needed for balance or support. Once reaching a leading edge, the worker can then lock the cable reel by pulling the handle  40  outwardly relative to the housing front surface  14  and rotating the handle until the shear pin is aligned with the locking slot  32 . The worker can then release to handle  40  so that the shear pin will be received in the locking slot  32 . By pulling the handle outwardly, the worker has brought the pinion gear  52  into engagement with the drum gear  50 . 
         [0031]    With the drum gear  50  locked in position the worker can pull against the retractable lifeline device  10  without the lanyard being able to extract. This enables the worker to establish a stable work position by leaning against the retractable anchorage. Should the worker fall in this position with the drum gear  50  locked in place it will cause a rotating load to be transferred to the pinion gear  52  and thereby to the shear pin  46 . The shear pin  46  is sized so that the pin will shear when a load greater than 400 lb (˜1780 N) is applied. When the pin shears, there will be nothing preventing the handle shaft  46  from moving axially, and hence nothing holding the pinion gear  52  in engagement with the drum gear  50 . Hence, the biasing element  56  will push the pinion gear  52  out of engagement with the drum gear  50 , allowing for the drum gear  50  and drum  18  to rotate. This then allows the retractable inner shock absorber to engage ensuring a fall arrest force on the worker. Preferably, the fall arrest force does not exceed 900 lbs (˜400 N). 
         [0032]    Turning to  FIGS. 8A-9B , a retractable lifeline assembly  110  is shown with an alternative boss and handle assembly. The lifeline assembly  110  is substantially the same as the lifeline assembly  10  ( FIGS. 1-7 ), and hence, the same reference numbers will be used to identify identical parts. The parts that are different will be preceded with a “1” (hence, “10” became “110). The lifeline assembly  110  includes a housing  12  containing a drum  18  rotatable about an axle  20 . A lanyard  24  is wound around the drum and exits the housing  12  via an exit  26  at the bottom of the housing. 
         [0033]    Turning to  FIGS. 9A  and B, the boss  130  extends from the front portion  14  of the housing  12 . As seen, the boss  130  is a separate piece, and is securely welded into place over an opening  131  in the housing front portion  14 . The boss  130 , like the boss  30 , comprises a pair of intersecting slots on an outer side of the boss, with one slot being deeper than the other, and a bore  136 . The locking slot  132  is shown in  FIG. 9A . On an inner side, the boss  130  includes a cavity  133  which opens into the inside of the housing  12 . An annular channel  135  extends outwardly from a surface of the cavity  133 . 
         [0034]    A shaft  144  extends through the bore  136  of the boss  130 , and the pinion gear  52  is mounted to an inner end of the shaft  144 . A shear pin  146  extends through the shaft  144  substantially normal to the shaft, and is sized and shaped to be received in the two slots of the boss  130 , in the same manner as the shear pin  46 . The bore  136  is wider than the shaft  144 , and a bearing  147 , such as a journal bearing, is received in the bore  136  through which the shaft  144  extends. The bearing  147  maintains the shaft  144  centered with respect to the bore  136  and facilitates rotation of the shaft  144  in the bore  136 . A washer  149  is positioned an the surface of the pinion gear  52  facing the shaft  144 . The washer  149  has a central platform  149   a  and a peripheral flange  149   b.  A coil spring  156  is positioned around the shaft  144 , and extends between the pinion gear  152  and the boss  130 . One end of the coil spring  156  engages the washer  149  and the opposite end of the coil spring is received in the annular channel  135  in the boss cavity  133 . As can be appreciated, the annular channel  135  and the washer  149  maintain the coil spring centered relative to the shaft  144 . 
         [0035]    Externally, a handle  140  comprising a pull member  142  is secured to the shaft  144 , for example, by means of screws which extend through the pull member  142  into screw holes  144   a  in the shaft  144 . The pull member  142  is in the form of a cap comprising an end surface  142   a  and a side surface  142   b,  which, in combination, define a circular area that is sized to receive the end of the boss  130 , and which can rotate relative to the boss  130 . 
         [0036]    As noted above, the pull member  142  is fixed to the shaft  144 , which in turn is fixed to the pinion gear  52 . Thus, by pulling the pull member  142  outwardly, the pinion gear  152  is moved from the position shown in  FIG. 9A  in which it engages the drum gear  50  to the position shown in  FIG. 9B  in which it is disengaged from the drum gear. The pinion gear can be held in this position by rotating the pull member  142  such that the shear pin  146  is received in the shallower slot. By pulling the pull member outwardly to the position at which it can be rotated, the handle assembly  140  can be switched to a position in which the shear pin is in the deeper slot, and thus in which the pinion gear and the drum gear are engaged. As can be appreciated, operation of the handle assembly  140  is thus substantially the same as for the handle  40 . 
         [0037]    As with the life line assembly  10 , when the lifeline assembly  110  is in the locked position (as shown in  FIGS. 8A and 9A ), the drum is prevented from rotating, and the lanyard therefore cannot be extended or retracted. Again, and as with the lifeline assembly  10 , if more than a predetermined amount of rotational force or torque (i.e., about 400 lbs or about 1780 N) is applied to the shear pin  146 , the shear pin will break. As seen in  FIG. 3B , the pinion gear  52  is positioned inwardly of the drum gear  50  (i.e. further from the housing front portion  14 ) when the lifeline assembly  10  is in the unlocked position. However, as seen in  FIG. 9B , the pinion gear  52  is positioned outwardly of the drum gear  50  (i.e., closer to the housing front portion  14 ) when the lifeline assembly  110  is in the unlocked position. Hence, in the lifeline assembly  110 , when the pin  52  in the lifeline assembly  110  shears, there will be nothing preventing the handle shaft  144  from rotating, and hence nothing holding the pinion gear  52  stationary with respect to the housing. Thus, the pinion gear  52 , even though still engaged with the drum gear  50 , is now free to rotate with the drum gear  50  and the drum  18 . This then allows the retractable inner shock absorber to engage ensuring a fall arrest force on the worker. Preferably, the fall arrest force does not exceed 900 lbs (˜400 N). 
         [0038]    As can be appreciated, the retractable lifeline provides a mechanism that the worker can use to lock the cable reel at any desired location. This ability to lock the cable reel enables the worker to adjust the retractable lanyard length to prevent the onset of a fail at dangerous locations such as roof edges. This ability to lock the reel also enables the worker to lean against the lanyard for stability such as when leaning out into areas where no other support is provided (such as changing light bulbs in hard to reach areas on the sides of buildings). From one anchorage position for the retractable lifeline, the worker can remain attached while moving and repositioning to new work areas. The locked lanyard line then acts as a travel limiter telling the worker that he has reached the boundary edge even if he is not watching or cannot see his exact position in dim lighting. 
         [0039]    As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, the boss  18  could be provided with a sloped surface having a slot at an upper end of the sloped surface and a stop at the lower end of the sloped surface. The shear pin would ride along the sloped surface as the T-handle is rotated relative to the boss to move the pinion gear into engagement with the drum gear. The slot at the top of the sloped surface would be sufficiently deep to retain the shear pin in the slot against rotational forces which might be applied to the shear pin. As shown and described the pinion gear is in the locking position when the shear pin is received in the shallow slot. However, the position of the pinion gear and/or the drum gear could be altered such that the pinion gear is in the locking position when the pinion gear is in the deep slot. Although the boss extends from the housing, the housing could be constructed such that the slots which receive the shear pin are in the surface of the housing, to present a generally flush surface to the housing. The shear pin could be replaced with spring mounted balls which are then received in detents. The spring mounted balls could be positioned in either the boss hole or the handle shaft, and the detents would be in the opposite of the two. The spring, in this, instance would be sized such that a 400 lb rotational force applied to the spring would cause the ball to disengage the detent, to allow the pinion gear to move from the locked position to the unlocked position. Although the shear pin receiving slots are shown to intersect at right angles, the slots could intersect at alternate angles. Although pinion gear is described to be axially movable relative to the drum or ring gear and the drum gear is axially fixed in place relative to the housing, the retractable lifeline device could be constructed such that the drum, and hence the drum gear, is movable axially relative to the pinion gear, and the pinion gear is fixed axially relative to the housing. In this instance, the drum gear would be moved into and out of engagement with the pinion gear via operation of the T-handle  30  to switch the retractable lifeline  10  between is locked and unlocked positions. These examples are merely illustrative.