Abstract:
An anchoring assembly is provided for the aerial lift platform of an aerial lift vehicle. The anchor assembly extends through the walls of a bucket liner and a bucket platform, and provides a strong anchor disposed inside of the bucket liner for use in attaching an operator harness to prevent the operator from being ejected from the bucket platform. The anchor assembly also provides dielectric protection mandated by OSHA and ANSI standards.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 62/180,210, entitled AERIAL LIFT PLATFORM WITH DIELECTRIC ANCHOR, filed on Jun. 16, 2015, the entire disclosure of which is expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     2. Field of the Disclosure 
     The present disclosure relates to an aerial lift platform for use with an aerial lift vehicle, the platform including a dielectric anchor. 
     3. Description of the Related Art 
     Aerial lift platforms are used by utility companies, arborists and others to allow an operator to safely work at an elevated position. The platforms typically include a semi-enclosed “bucket” structure made of a dielectric material, such as fiberglass or plastic, or of an electrically conductive material, such as a metal or metal alloy, which is attached to the end of the lifting boom of an aerial lift vehicle. In order to provide protection from electrical shock to an operator within the bucket, the bucket may be fitted with an internal electrically insulating bucket liner. The dielectric integrity of the bucket liner requires a continuous, uninterrupted enclosure to provide electrical shock protection for the operator, wherein any open holes, fractures, cracks, or thin wall portions can potentially result in dielectric failure of the bucket liner. Notwithstanding the foregoing potential for dielectric failure, bucket liners are a well proven, and often required, piece of safety equipment in particular applications. 
     In addition to the danger of potential exposure to electric shock, operators of aerial lift platforms also face the risk of being ejected from the bucket while working in an elevated position. For example, an external object striking the aerial lift vehicle may cause a may result in the operator being ejected from the bucket. In order to mitigate this risk, many harness/lanyard and fall arresting devices are currently available, which require an attachment point to a strong anchor point, typically a location on the lifting boom of the aerial lift vehicle. The length of the lanyards and the design of the harnesses are intended to minimize injury to the operator if the operator is ejected from the bucket. However, the use of these devices is somewhat cumbersome, and requires a varying degree of proper installation for correct function. Additionally, even when these devices function correctly, the experience of being ejected from the bucket while at an elevated height is traumatic for the operator. 
     What is needed is an improvement over the foregoing. 
     SUMMARY 
     The present disclosure provides an anchoring assembly for the aerial lift platform of an aerial lift vehicle, which provides a strong anchor point disposed inside of a bucket liner for preventing an operator from being ejected from the bucket, and also provides dielectric protection mandated by OSHA and ANSI standards. 
     In one form thereof, the present disclosure provides a platform for use with an aerial lift vehicle, including a bucket including a first bottom wall and at least one first side wall, and a first hole in one of the first bottom wall and the first side wall; a bucket liner received within the bucket, the bucket liner including a second bottom wall and at least one second side wall, and a second hole in one of the second bottom wall and the second side wall, the second hole in alignment with the first hole; and an anchor assembly extending through the first and second holes, the anchor assembly including an anchor point disposed internally within the bucket liner; and a cover assembly disposed externally of the bucket. 
     In another form thereof, the present disclosure provides a platform for use with an aerial lift vehicle, including a bucket including a first bottom wall and at least one first side wall, and a first hole in one of the first bottom wall and the first side wall; a bucket liner received within the bucket, the bucket liner including a second bottom wall and at least one second side wall, and a second hole in one of the second bottom wall and the second side wall, the second hole in alignment with the first hole; and an anchor assembly extending through the first and second holes, the anchor assembly including an anchor point disposed internally within the bucket liner, the anchor point including a shaft extending through the aligned first and second holes, the shaft having an end disposed externally of the bucket. 
     In a further form thereof, the present disclosure provides a bucket liner for use with a platform of an aerial lift vehicle, including a bottom wall and at least one side wall, and a hole in one of the bottom wall and the side wall; and an anchor assembly extending through the hole, the anchor assembly including an anchor point disposed within the bucket liner; and a cover assembly disposed externally of the bucket liner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above mentioned and other features and objects of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description of embodiments of the disclosure taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a side view of an aerial lift vehicle including a lifting boom and platform including a bucket; 
         FIG. 2  is a partial perspective and exploded view of the end portion of the lifting boom of the vehicle of  FIG. 1 , further showing a bucket and bucket liner; 
         FIG. 3  is a perspective view of the bucket and bucket liner of  FIG. 2 , including an anchor assembly according to the present disclosure; 
         FIG. 4  is a sectional view taken along line  4 - 4  of  FIG. 3 , further showing a clasp and a portion of a harness assembly; 
         FIG. 5  is an exploded view of components of the dielectric anchor assembly of  FIGS. 3 and 4 ; 
         FIG. 6A  is a further sectional view of a dielectric anchor assembly, corresponding to the location of line  4 - 4  of  FIG. 3 , showing a modified bucket; and 
         FIG. 6B  is a fragmentary perspective view of a portion of  FIG. 6A . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplifications set out herein illustrate embodiments of the disclosure, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the disclosure to the precise form disclosed. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an aerial lift vehicle  20  is shown in the form of an aerial lift truck, which includes a lifting boom assembly  22  having a boom arm  24  for supporting platform  26  at a selected elevated position to enable an operator to perform various tasks at an elevated height, such as servicing or installing electrical power lines, servicing or installing data transmission equipment, or trimming trees, for example. 
     Referring to  FIG. 2 , platform  26  is shown as a “bucket” type platform, generally including an outer bucket  28  and an internal bucket liner  30  received within bucket  28 . Bucket  28  may be made of a dielectric or electrically conductive material, such as fiberglass, plastic, or a metal or metal alloy, for example, with suitable materials including carbon fiber, aluminum, and steel. Bucket  28  includes front wall  30   a , rear wall  30   b , left wall  30   c , right wall  30   d , and bottom wall  32  which together provide bucket  28  with a generally rectilinear configuration having an open upper end and an open interior  34 . Bucket  28  may additionally have an upper edge  36  corresponding to the upper ends of its side walls, namely, front wall  30   a , rear wall  30   b , left wall  30   c , and right wall  30   d , which may optionally be configured as a horizontal upper lip or flange extending around upper edge  36  of bucket  28 . 
     In the bucket construction depicted in  FIG. 2 , rear wall  30   b  of bucket  28  includes a rigid boom mount plate  38 , typically made of a high strength metal or metal alloy, embedded within the material of rear wall  30   b  and/or attached exteriorly to wall  30   b . Boom mount plate  38  includes a boom attachment structure shown as a series of fixation points  40  which, for example, may be threaded apertures within, or bolts extending from, boom mount plate  38 . The end of boom arm  24  includes a corresponding mount plate  42  having a corresponding series of fixation points  44  for securement to the fixation points  40  of mount plate  38  of bucket  28 . However, as will be apparent from the discussion below, the particular manner in which bucket  28  is secured to the end of boom arm  24  may vary depending on the particular structure of boom assembly  22 , and the present anchor assembly is not limited to any particular type of securement mechanism between bucket  28  and the end of boom arm  24 . Further, as also discussed below, the present anchor assembly is retro-fittable onto any type of aerial lift platform regardless of the particular interface used to connect the platform and the boom. 
     In a first embodiment, a rigid anchor plate  46 , typically made of a high strength metal or metal alloy, and having a hole or aperture  48  for fixation of the present anchor assembly, may also be embedded within the material of rear wall  30   b  of bucket  28 . Anchor plate  46  may be separate from, or may be an integral part of, boom mount plate  38 . Alternatively, anchor plate  46  may be embedded within, or otherwise associated with, any of front wall  30   a , left wall  30   c , right wall  30   d , or bottom wall  32  of bucket such that, as described further below, the location of the present anchor assembly with respect to bucket  28  may vary. 
     Bucket liner  30  is received within bucket  28  and, similar to bucket  28 , also includes front wall  50   a , rear wall  50   b , left wall  50   c , right wall  50   d , and bottom wall  52  which together provide liner  30  with a generally rectilinear configuration having an open upper end and an open interior  54 , which is complementary to the shape of bucket  28  such that liner  30  may be received within bucket  28 , typically via a substantially close fit. Liner  30  may additionally have an upper edge  56  corresponding to the upper ends of it side walls, namely, front wall  50   a , rear wall  50   b , left wall  50   c , and right wall  50   d , which may optionally be configured as a horizontal upper lip or flange extending around upper edge  56  of liner  30 , and which may be shaped in a complementary manner to interface with the upper edge  36  of bucket  28 . Rear wall  50   b  includes a hole or aperture  58  though, as described below, hole or aperture  58  may be located elsewhere on any other wall of liner  30 . In particular, hole or aperture  58  may be alternatively located in front wall  50   a , left wall  50   c , right wall  50   d , or bottom wall  52 , with the corresponding hole or aperture of bucket liner  30  aligned therewith, as described below and shown in  FIG. 4 . Liner  30  is made of a dielectric material, such as fiberglass or a plastic such as polyethylene. 
     Although bucket  28  and liner  30  are shown and described herein as having a rectilinear shape, the particular shapes of bucket  28  and liner  30  are not critical, and bucket  28  and liner  30  may have other shapes, such as round or oval, and it will be apparent from the present disclosure that the anchor assembly of the present disclosure may be used with buckets and liners having shapes other than rectilinear. 
     Referring to  FIGS. 3-5 , an anchor assembly  60  in accordance with a first embodiment of the present disclosure is shown, which generally includes a rigid anchor point disposed within the interior  54  of liner  30 , as well as a cover assembly disposed externally of bucket  28 . The anchor point of anchor assembly  60  generally provides a firm anchoring or fixation point for securing a clip fastener or other attachment structure associated with a harness assembly that may be worn by a worker positioned within the aerial platform  26 . The cover assembly provides a dielectric cover or protective enclosure for anchor assembly  60  externally of bucket  28  in order to isolate any electrically conductive components of anchor assembly  60  from the environment externally of platform  26 , as also discussed further below. 
     Referring to  FIGS. 4 and 5 , with liner  30  received within bucket  28 , rear wall  50   b  of liner  30  is disposed adjacent rear wall  30   b  of bucket  28 , with the forgoing walls either in direct contact with one another as shown in  FIG. 4 , or alternatively, spaced very closely adjacent one another with a small air gap space between rear wall  50   b  of liner  30  and rear wall  30   b  of bucket  28 . 
     Anchor member  62  is made of a rigid material, such as a metal or metal alloy or a rigid plastic, for example, and includes an anchor ring  64  to which a clip  66  ( FIG. 4 ) of a harness assembly  67  of the type worn by a user may be secured. Anchor member  62  also includes anchor plate  68  and shaft  70  having a threaded end  72 . An optional internal insulating pad  74 , made of a dielectric material such as plastic or rubber, for example, may be disposed between anchor plate  68  and the interior surface of rear wall  50   b  of liner  30 , and may further include an annular boss portion  76  disposed between the interior of hole  58  in rear wall  50   b  of liner  30  and shaft  70  of anchor member  62 . Shaft  70  extends through holes  48  and  58  in rear walls  32   b  and  50   b  of bucket  28  and liner  30 , respectively. 
     An insulating housing  78  is disposed on the exterior side of rear wall  30   b  of bucket  28 , and is formed as a cup-shaped member including a bottom wall  80 , a cylindrical side wall  82 , and a central hole or aperture  84 . Housing  78  is made of a dielectric material, such as a rigid plastic, for example. An optional external anchor plate  86  is disposed within housing  72 , and includes a central hole  88  such that anchor plate  86  may be received over the threaded end  72  of shaft  70  of anchor member  62 . External anchor plate  86  may be made of a suitable metal, metal alloy, or a rigid plastic, for example. Optionally, an insulating pad (now shown) similar or identical to insulating pad  74 , may be disposed between rear wall  30   b  of bucket  28  and housing  78 . A metal or rigid plastic retaining device, such as a nut  90 , is threaded over the threaded end  72  of shaft  70  to tightly capture the above-described components against one another in a multilayer structure. 
     Specifically, tightening of nut  90  draws the above-described components tightly together in the manner shown in  FIG. 4 , with internal anchor plate  68  of anchor member  62  and internal insulating pad  74  tightly and sealingly pressed against the interior surface of rear wall  50   b  of liner  30 , and housing  78  and external anchor plate  86  tightly and sealingly pressed against the exterior surface of rear wall  30   b  of bucket  28 . The foregoing assembly forms a rigidified anchoring construction in which there are no fluid pathways present between the interior  54  of liner  30  and the environment outside of bucket  28 . In this manner, the interior  54  of liner  30  is electrically insulated from the environment outside of bucket  28 . 
     Housing cover  92  is made of a dielectric material, such as a rigid plastic, and includes a side wall  94  having exterior threads  96  for threaded engagement with interior threads  98  of cylindrical wall  82  of insulating housing  78 . Cover  92  includes an integral tool fitting, such as a projecting hex nut  100 , for example, which may be engaged by a suitable tool for installing cover  92  onto housing  78  or removing cover  92  from housing  78 . When cover  92  is secured in place, any metallic components of anchor assembly  60  that are disposed on the exterior side of bucket  28 , such as shaft  70 , external anchor plate  86 , and nut  90 , are electrically insulated or sealed from the environment outside of bucket  28 . Also, an insulating air space  93  may be present in an interior of housing  78  when cover  92  is attached to housing  78  as described above. 
     In this manner, anchor assembly  60  provides a rigid anchor point within a wall of bucket  28  and liner  30 , which is exposed within the interior  54  of liner  30  for securement of the harness assembly of an operator, wherein all of the metallic components of anchor assembly  60  are electrically insulated from the environment outside of bucket  28 . Also, anchor assembly  60  provides a secure connection between bucket  28  and liner  30 , preventing liner  30  from being ejected from bucket  28 . 
     Notably, the present anchor assembly  60  was developed in contravention to the existing design knowledge in the art, in which known anchor assemblies have avoided any type of hole or aperture in any of the side walls or bottom wall of the bucket or bucket liner. Stated otherwise, conventional anchoring structures known in the art were specifically developed to maintain the complete structural integrity of the side walls and the bottom wall of the bucket and bucket liner. This approach was previously thought necessary for a bucket liner to pass existing electrical integrity tests used in the art, such as ANSI A92.2 sections 4.94, 5.4.2.5, and/or 5.4.2.5 (2009), in which a bucket liner is submerged within a water tank such that the depth of the water is within about 6 inches from the upper lip of the bucket liner, both outside and inside of the liner. In this manner, the water inside the liner is nominally electrically isolated from the water outside of the bucket liner. An electrical current is then provided to the water within the tank and outside of the bucket liner, with a meter disposed within the interior of the bucket liner to determine whether any electrical current passes from the water in the tank outside of the bucket liner to the water in the interior of the bucket liner. In a successful test, current leakage recorded by the meter remains below a specified value, indicating the dielectric integrity of the bucket liner. In an unsuccessful test, current leakage recorded by the meter exceeds a specified value, indicating a failure in the dielectric integrity of the bucket liner, which may be due to cracks or fissures in a wall of the bucket liner, for example. 
     Advantageously, despite the presence of hole  58  in liner  30  with which anchor assembly  60  is used, the foregoing dielectric integrity test may be met by a bucket liner including the anchor assembly of the present disclosure. Specifically, for testing the liner  30 , anchor assembly  60  may be disassembled by removing housing cover  92  and nut  90 , followed by removal of the remaining components of anchor assembly  60  from bucket  28  and liner  30 , such that liner  30  may itself be removed from bucket  28 . Following removal of liner  30  from bucket  28 , anchor assembly  60  may be reassembled to liner  30  in the manner described above through hole  58  about the internal and exterior surfaces of the wall of liner  30 , followed by placing liner  30  within a water tank according to the above-described test. In this manner, the testing configuration of liner  30  and its anchor assembly  60  is identical to that of the installed configuration shown in  FIG. 4 , only without the presence of the wall  30   b  of bucket  28  and the harness assembly  67  and its clip  66 . During the test, external insulating housing  78  and housing cover  92  electrically isolate any metallic components of anchor assembly  60  from the water in the tank to prevent the passage of electric current from the water in the tank through liner  30  and into the interior  54  of liner  30 . 
     Referring to  FIGS. 6A and 6B , an anchor assembly  102  according to a further embodiment of the present disclosure is shown. Except as described below, the components of anchor assembly  102  are identical or substantially identical to those of anchor assembly  60 , and identical reference numerals will be used to designate such identical or substantially identical components. A secondary anchor plate  104  is secured to the exterior and/or interior side of rear wall  30   b  of bucket  28 , which includes an upper portion  106  having a hole or aperture  108  therein for receipt of anchor assembly  102 , as well as a lower portion  110  which may be disposed at an angle relative to upper portion  106 , and which includes an external anchor plate in the form of a hole or aperture  112 . A connection device, such as a chain or fabric webbing, may be secured to hole  112  in lower portion  110  of external anchor plate  104  to secure same to boom arm  24  ( FIG. 2 ). Alternatively, secondary anchor plate may be secured to another wall of bucket  28 , such as front wall  30   a , left wall  30   c , right wall  30   d , or bottom wall  32   
     Advantageously, as may be seen in connection with each of the embodiments of the anchor assemblies described above, the anchor assemblies may be retro-fittable onto any existing platform structure, regardless of the specific connection mechanism that is used to secure the platform  26  to the boom arm  24 , such as by forming a hole through the walls of an existing bucket liner and/or bucket. Additionally, the location of the anchor assembly on the platform  26  may vary widely. For example, anchor assembly  60  or  102  may be disposed at substantially any location within the side walls of the bucket and bucket liner, or even in the bottom wall of the bucket and bucket liner. 
     In one embodiment, the anchor assembly is mounted to the platform  26  in a manner in which the anchor ring  64  or the shaft  70  of anchor member  62  is disposed adjacent upper edge  56  of bucket liner  30  or, in another embodiment, is disposed at least 6 inches from upper edge  56  in a direction from upper edge  56  toward bottom wall  52 . In a still further embodiment, the anchor ring  64  or the shaft  70  of anchor member  62  may be disposed at least 30 inches from bottom wall  52  in a direction from bottom wall  52  toward upper edge  56  of liner  30 , such as between 39 and 42 inches from bottom wall  52  in a direction from bottom wall  52  toward upper edge  56  of liner  30 , for example. 
     Still further, although the embodiment of  FIGS. 3-5  shows anchor assembly  60  including a metal anchor plate  46  embedded within a wall of bucket  28 , and the embodiment of  FIGS. 6A and 6B  includes an external anchor plate  104  secured to a side wall of bucket  28 , in a further embodiment, such plates could be eliminated such that the anchor assembly is positioned at any desired location within any side wall or bottom wall of bucket  28  and liner  30  by forming aligned holes at a desired location within the side wall or bottom wall, followed by installing the anchor assembly at such location in manner described above. 
     While this disclosure has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.