Abstract:
A guardrail system for a mobile machine&#39;s cab environment for temporarily enclosing an open access area of a walkway. The walkway includes a fixed rail portion, a rail panel assembly having a rail docking assembly and an access walkway. The rail panel assembly including at least one leg member defining an engagement portion of the at least one leg member, and a receiving portion defined by the access walkway. The rail docking assembly comprising of at least one first bracket, at least one second bracket, and a fastener. The first bracket being attachable to the fixed rail portion and the second bracket being attachable to the rail panel assembly, wherein the engagement portion of the at least one leg member being engageable with the receiving portion of the access walkway corresponding to the open access area being at least partially enclosed by the rail panel assembly, wherein the second bracket and corresponding rail panel assembly being removably attachable to the first bracket and corresponding fixed rail through the fastener.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates generally to a guardrail system for enclosing an open access walkway of a machine. In particular, a guardrail system to enclose a portion of the walkway of the machine in proximity to the operator cabin of a mobile machine. 
       BACKGROUND 
       [0002]    Off-highway machines, such as large mining trucks, are used to transfer material from one place to other. The material is carried in a load-body that can be tilted from a substantially horizontal position to an acute angle or inclined position such that the material slides out of the load-body. The inclined position is preferred during offloading of the material being carried, and the horizontal position is preferred during the storing and transfer of the material. 
         [0003]    During the service operations of such machines the load-body may be required to be in a tilted-up position. In the tilted-up position, an operator may have access to equipment panels built into the rear portion of an operator cab to reveal components such as an aftertreatment module, fluid reservoirs or filters that require periodic maintenance. During such service operations, the load-body is securely locked in the tilted-up position, and an alarm system may also be installed to notify operator, in case the load-body is tilted up however not in the locked position. 
         [0004]    In current machines, an operator may face challenges relative to keeping stable footing as there may be slippery portions of the walkway surrounding the cab especially at the rear of the operator cabin. This situation may be further exacerbated at the site of the rear of the cab since there exists no handrail for the operator to grasp to regain footing because such handrail would interfere with the load-body as it is returned to the horizontal position. 
         [0005]    U. S. Pat. No. 8,801,041 B2 relates to a fluid storage container and method. The fluid storage container includes a tank for storing fluid and a working surface area walkway built into an end of the tank. There are handrails on the walkway that can be positioned depending on the required function of the tank. The fluid storage container includes a receptacle to secure leg portions of the handrails to erect the handrails when it is desired to have a handrail. A safety chain connects between handrails of adjacently parked containers. The position of handrails can be shifted from a storage configuration to an “in-place” configuration, as required and the leg portions of the handrail are slid into the associated receptacles. The receptacles are permanently attached to a perimeter of the walking area for receiving the leg portions of the handrail and once erected the handrails provide a barrier along an edge of the walkway. Additional receptacles are positioned next to a wall area of the storage container to receive the leg portions of the barriers for the purpose of storing the handrails out of the way and next to the fluid storage container when not required. 
         [0006]    The patent &#39;041 requires the receptacles to be permanently fixed to the portions of the walkway for receiving the handrails in both the stored and operable-barrier positions. Such constrains describes a definite stored positions of the handrails, defined by the strategic placement of the receptacles. Therefore, such designs are adaptable to commonly used structures such as fixed guardrails. The prior art fails to identify a flexible mounting location for storage of handrails and lacks strength to support wider and heavier handrails for an operator support. 
       SUMMARY OF THE INVENTION 
       [0007]    In accordance with one aspect of the present disclosure, a guardrail system for a mobile machine&#39;s cab environment is provided for temporarily enclosing an open access area of a walkway. The open access area of walkway includes a fixed rail portion, a rail panel assembly and a rail docking assembly. The fixed rail portion is firmly attached along the edges of the walkway, wherever required at predefined locations. The rail panel assembly including at least one leg member defining an engagement portion of the at least one leg member, and a receiving portion defined by the access walkway assembly. The rail docking assembly comprising at least one first bracket, at least one second bracket, and a fastener. In one aspect of the invention, the first bracket is attached to the fixed rail portion and the second bracket is attached to the rail panel assembly, wherein the engagement portion of the at least one leg member of the rail panel assembly is engaged with the receiving portion of the access walkway assembly corresponding to the open access area, that is being at least partially enclosed by the rail panel assembly. In another aspect of the invention, the second bracket and corresponding rail panel assembly is removably attached to the first bracket and corresponding fixed rail, through the fastener. Thus, the rail panel assembly can be removably attached to the open access area of walkway or at any location to the fixed rail portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a mobile machine illustrating a raised load-body with rail panel assemblies in a stored position along fixed rail portions of the machine according to the concepts of the present disclosure; 
           [0009]      FIG. 2  is a perspective view of the front portion of the machine of  FIG. 1  with all other aspects of the machine removed to illustrate the rail panel assembly of the guardrail system being removably coupled to the fixed rail portion of the machine through a rail docking assembly, according to the concepts of the present disclosure; 
           [0010]      FIG. 3  is an exploded view of the guardrail system of  FIG. 2 , illustrating the assembly of the rail panel assemblies in a stored position, according to one aspect of the disclosure; 
           [0011]      FIG. 4  is a perspective view of the guardrail assembly in association with a rear portion of the cab shown in  FIG. 2 , with the rail panel assemblies deployed to form a closed enclosure for the access walkway according to an aspect of the present disclosure; 
           [0012]      FIG. 5  is a perspective view of the guardrail system of  FIG. 2 , with the rail panel assemblies deployed and the cab removed to illustrate the guardrail system enclosing an access area of a walkway of the machine, according to concepts of the present disclosure; and 
           [0013]      FIG. 6  is an enlarged, exploded view of the encircled portion of  FIG. 3 , illustrating the rail docking assembly, according to an embodiment of the present disclosure. 
           [0014]      FIG. 7  is an enlarged, exploded view of the encircled portion of  FIG. 4 , illustrating the engagement of leg member into receptacles, according to an embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts. 
         [0016]      FIG. 1  illustrates an exemplary mobile machine  10 . In the illustrated embodiment, the mobile machine  10  is an off-highway truck. However, the present disclosure may be embodied in any type of machine having unenclosed portions of access walkway, for example, large mining trucks, off-road haul trucks, excavators, track loaders, and the like. The mobile machine  10  may be interchangeably called as machine, in the rest of the description. In accordance with the concepts of this disclosure, the mobile machine  10  includes a frame  12 , a front portion of the machine  14 , a rear portion of the machine  16 , a load-body  18  having a front side  78  and a rear side  80 , wheels  20 , and an operator station  22 . The mobile machine  10  may be operated by receiving power from an internal combustion engine (not shown) or by any other known methods in the art such as an electrical generator, assembled to the frame  12  of the machine  10 . In the current embodiment, the frame  12  is assembled substantially parallel to ground, supported on wheels  20  via wheel axles (not shown). 
         [0017]    The rear portion  16  of the machine  10  includes the load-body  18  pivotally connected to the frame  12 . The load-body  18  is used for carrying material and dump the material by raising the load-body  18  generally away from the machine&#39;s frame  12  as is customary. The movement of load-body  18  during a typical dump cycle is actuated by a hoist assembly  42  located between the front and rear wheel axles (not shown). The hoist assembly  42  includes a hydraulic cylinder  43  however it may be powered by electrical or mechanical means as well as through hydraulic activation. The hoist assembly  42  includes two ends (not shown), one end is fixed to the frame  12  and the other end may be attached to the bottom side of the load-body  18 . The fully extended hoist assembly  42  coincides with the load-body  18  being fully raised from a load carrying mode i.e. typically parallel to the ground, to a load dumping mode i.e. the front portion of the load-body  18  at a higher potential with respect to the rear portion of the load-body  18 . Although, a hydraulic cylinder type hoist assembly  42  is disclosed in the current embodiment, any other type of load-body lifting mechanism may be employed, as known in the art. 
         [0018]    The load-body  18  may include a canopy portion  19  on the front side  78  of the load-body  18 , to provide protection to the operator station  22  from foreign objects that may be deflected from the operator station  22  during operation of the machine  10 . In the load carrying mode, the position of the canopy portion  19  and portions of the load-body  18  are within proximity to the operator station  22 . 
         [0019]    As illustrated in  FIG. 2 , a guardrail system  23  is shown in proximity to the front portion of the machine  14  and includes an access walkway assembly  24  enclosed by a fixed rail portion  26 . The access walkway assembly  24  is typically designed to surround a generally horizontally positioned deck area around the operator station  22  to provide access for the operator or service personnel to access the operator station for servicing or maintenance, for example. The access walkway assembly  24  thus formed, not only provides access to a door  28  of the operator station  22  but also provides access to servicing/maintenance of components, such as windshield, rear window, side window, electrical/electronic components, etc. 
         [0020]    The fixed rail portion  26  extend upwards from the access walkway assembly  24  in a vertical direction. The fixed rail portion  26  is typically provided on the front and side portions of the access walkway assembly  24  and not provided in the rear side of the operator station  22 , due to the interference of the load-body  18  with the operator station  22  in the load carrying mode. This creates an open access area  34 . The fixed rail portion  26  may be a single continuous assembly or an assembly of multiple fixed rail portions, attached to each other. In the current embodiment, two fixed rail portions  64  and  66  are assembled to the access walkway assembly  24  near the front left side of the mobile machine  10 . The two fixed rail portions  64  and  66  are attached to each other by hinge members  62 . The fixed rail portions  64  and  66  are structurally supported using pillars  30  and fixtures  32 . 
         [0021]    The fixed rail portions  64  and  66  include fixed guardrails  27  and the fixed guardrails  27  may be manufactured from steel bars, tubes or channels and be welded or bolted together as is customary. The fixed guardrails  27  are assembled with the fixed rail portions  64 ,  66 , to provide strength to the rail however the rail must not obstruct the view of an operator seated in the operator station  22 . The hinge members  62  may be a simple bolt and nut joint or a pint joint or any other hinge assemblies know to those with ordinary skill in the art. 
         [0022]    As illustrated in  FIG. 2 , in an embodiment, a rail panel assembly  36  including portable rail panels  37  (shown in  FIG. 3 ) and leg members  38  are removably attached to the fixed rail portions  64 ,  66  via rail docking assemblies  44 . In an exemplary embodiment, the rail panel assembly  36  may be made up of a unitary assembly or it is envisioned that an assembly of multiple rail panels, may be assembled to result in a unitary assembly. In the current embodiment, two rail panel assemblies  68  and  70  are removably connected or “docked” with the fixed rail portions  64  and  66 , respectively so as to allow an operator expedient access to such removable panels in preparation for assembling the same in a fixed positioned as will be hereinafter explained. 
         [0023]    As shown in  FIG. 3 , each rail docking assembly  44  includes a first bracket  46  located on the portable rail panel  37  and a second bracket  48  located on the fixed guardrails  27 . In an embodiment, details of the first bracket  46  and the second bracket  48  are illustrated in  FIG. 6  and described hereon. The first bracket  46  includes a first end  50  and a second end  52 . The first end  50  of the first bracket  46  is integrally attached to each of the portable guardrails  37  of the rail panel assemblies  68  and  70 . The second end  52  of the first bracket  46  includes a fastener guiding feature  53 , such as a through hole, for example. The second bracket  48  includes a first end  54  and a second end  56 . The first end  54  of the second bracket  48  is integrally attached to the fixed guardrail  27  of the fixed rail portions  64  and  66 . The second end  56  of the second bracket  48  includes a fastener securing feature  57 , such as a threaded hole, threaded boss, weld-nut etc. In illustrated embodiment, the fastener securing feature  57  is a threaded boss, being integrally attached to the second end  56  of the second bracket  48 . The integral attachment of first bracket  46  with the rail panel assemblies  68 ,  70  and the second bracket  48  with the fixed rail portions  64 ,  66 , may be achieved by welding, for example. A fastener  58  is used to couple the first bracket  46  and second bracket  48 . 
         [0024]    In an exemplary embodiment, the first bracket  46  along with the fastener guiding feature  53  of the second end  52  is attached to each portable guardrail  37  of the rail panel assemblies  68 ,  70  and the second bracket  48  along with the fastener securing feature  57  of the second end  56  is attached to the fixed guardrail  27  of the fixed rail portions  64 ,  66 , is illustrated. In another embodiment, it may be contemplated that the first bracket  46  may have the fastener securing feature and the second bracket  48  may have the fastener guiding feature. It is also envisioned that the fastener securing feature  57  is a unitary feature of the second end  56 , such as internal threads, for example. 
         [0025]    The current disclosure contemplates that other rail docking assembly constructions may be possible. For example, the first bracket  46  may be integrally attached to each portable guardrail  37  of the rail panel assemblies  36 , while the second bracket  48  may be free to slide and rotate along the centerline of the fixed guardrails  27  of the fixed rail portion  26  or vice-versa. As illustrated in  FIG. 4 , in one embodiment, the rail panel assemblies  68 ,  70  are shown undocked and positioned to enclose a rear portion of the access walkway assembly  24  in proximity to the rear of the operator station  22  corresponding to the truck body being raised. In this embodiment, the rail panel assemblies  68 ,  70  are detached from the fixed rail portions  64 ,  66  respectively, by unfastening the fasteners  58 . The detached rail panel assemblies  68 ,  70  are assembled in the open access area  34 , by coupling an engagement portion  40  of the leg members  38  to receptacles  61  placed within receiving portions  60  of the access walkway assembly  24 . The receptacles  61  are designed such that that the engagement portion  40  of the leg members  38  slid into apertures  86  of the receptacle  61  and provide enough support to the entire rail panel assemblies. 
         [0026]    Referring to  FIG. 7 , the receptacle  61  has a long c-shaped member that has apertures  86  on flange portions  82  and web portion  84  of the receptacle being attached to the access walkway assembly  24 . In an embodiment, the web portion  84  of the receptacles  61  may be bolted or welded to the sides of the walkway assembly  24 . The size of the apertures being slightly larger than the circumferential geometry of the leg members  38 , to provide easy assembly and disassembly. Also, the distance between the two flange portions  82  of the c-shaped receptacle  61  being sufficiently large enough, that it supports any lateral load applied on the rail panel assemblies  67 ,  70 . The leg members  38  have a tab portion  41  larger than the size of the aperture of the c-shaped member near the engagement portion  40 , so that when the tab portion  41  hit against the flange portion  82  of the receptacle  61 , the movement of leg member  38  is restricted. Thus, the rail panel assembly  36  may be coupled to the walkway assembly  24 . In an exemplary embodiment, the receiving portions  60  of the access walkway assembly  24  are placed such that the rail panel assembly  36  can be assembled at the desired location. In an exemplary embodiment, the fasteners  58  are captive type fasteners that always remain attached to the first bracket  46 . In another embodiment, while the rail panel assembly  36  is detached with the fixed rail portion  26 , the fasteners  58  may be stored by fastening them to the corresponding fastener securing portions  57  of the first bracket  46 . 
         [0027]    Referring to  FIG. 5 , the first rail panel assembly  68  is assembled to the receiving portion  60  of the walkway access  60  and supported by the second fixed rail portion via the support members  74 . The second rail panel assembly  70  is assembled to the walkway assembly  24 , supported by the first rail panel assembly  68 , and the rear side of the operator station  22  via support members  74 . Each support member  74  may be a u-shaped members welded to rail  27 ,  37  which engages a dual bar interlocking member  75  with a lock pin extending through a hole aligned through the u-shaped member and the dual bar interlocking member  75 , for example. In other embodiments, the support members  74  may be of any other known methods to quickly connect and disconnect the rail panel assembly  36  with the fixed rail portions  26 . The fixed rail portions  64 ,  66  and the rail panel assemblies  68 ,  70  are attached in an in-line fashion, as explained before, to provide complete protection for an operator over the access walkway assembly  24 . In an embodiment, rail panel assemblies  68  and  70  of different size and shapes may be used to enclose the open access area  34 . 
         [0028]    As illustrated in  FIG. 6 , the latching of rail docking assembly  44  to store the rail panel assembly  36  with the fixed rail portion  26  is shown. The fixed guardrails  27  of the fixed rail portion  26  or the portable guardrail  37  of the rail panel assembly  36  are covered with bumpers  76 . Each bumper  76  may be made of an elastomeric or plastic material and be assembled in between the first bracket  46  and the second bracket  48  of the rail docking assembly  44  to avoid the wear and tear of the rail panel assemblies being docked to the fixed rail assemblies  64 ,  66 . These bumpers  76  improve the life of the rails  27 ,  37 , due to frequent coupling/de-coupling of the rail panel assembly  36  with the fixed rail portion  26 . These bumpers may also be placed at other locations over the rails  27  of the rail panel assembly  36  to avoid cabin door being hit to the rails  27 , to provide additional grip and ergonomics to an operator. In an embodiment, these bumpers  76  may be attached by gluing them onto the guardrails  27  with the help of an adhesive, as ordinarily known in the art. 
       INDUSTRIAL APPLICABILITY 
       [0029]    The industrial applicability of a guardrail system  23  of a mobile machine  10  described herein will be readily appreciated from the foregoing discussion. As described earlier the mobile machine  10  includes, a load-body  18  attached to the frame  12  of the machine  10 . 
         [0030]    When the load-body  18  is in elevated and locked in an up position, the operator may have access to the rear portion of the access walkway assembly  24  for servicing or maintenance operations. In such situations, the walkway in proximity to the rear side of the operator station  22 , does not have a railing which may increase the risk of instability for the operator intending to traverse this part of the walkway. Moreover, the operator may desire to use safety harnesses when traversing this portion of the walkway since there lacks a guardrail however with the rail panels in place the operator may not require the safety harness as may be suggested in the operator&#39;s manual of the machine. Therefore, an enclosure for such open access area  34  is provided and may be removably mounted and also easily and conveniently stored. 
         [0031]    At the rear portion of the operator station  22 , several machine subsytems may be housed within compartments in the base of the operator station  22  such as the various fluid levels, filters, fuses, engine control module (ECM), wiring harness, switches, etc. An operator may be required to inspect these component during service or maintenance operations. Once the load-body  18  is raised and locked in the up position access to the walkway surrounding the rear portion of the cab is exposed to provide access for an operator to the open access area  34 . During maintenance to subsystems and components at the rear of the cab, the operator seeks to traverse the walkway however may require a safety harness to ensure he remains safe where there is not a rail. However, the use of the safety harness may be lessened or used, if at all, in compliance with practices suggested and established by the manufacturer. However, as is disclosed in the present disclosure the rail panels when erected provide a rail for the operator to stabilize himself when accessing the area of the walkway at the rear portion of the operator cab. This need for this additional guardrail may be even more critical in severe climates for example for use with machines operating in cold climate regions, wherein the access walkway assembly  24  may be slippery due to snow, ice, or sleet. Thus a portable rail support is provded at the perimeter of the open access area  34  at the rear portion of the cab&#39;s walkway, and a portable rail assembly that can be quickly assembled and disassembled during servicing and maintenance operations. The guardrail system  23  has been designed to solve this problem that will be explained hereinafter. 
         [0032]    The guardrail system  23  for the mobile machine  10  in the vicinity of the cab or operator station  22  includes the fixed rail portion  26  extending from the access walkway assembly  24 , a rail panel assembly  36 , and a rail docking assembly  44  that can quickly couple or decouple the rail panel assembly  36  to the fixed rail portion  26 . The rail panel assembly  36 , in an exemplary embodiment, may be one single unit made of integrating several pieces of tubes or channels. The rail panel assembly  36  includes leg members  38  having engagement portions  40  which are selectively engaged or “slid into” female receiving portions or features  60  secured to the walkway assembly  24 . 
         [0033]    In one aspect of the disclosure, a first configuration or stored configuration is described wherein the rail panel is assembled  36  to the fixed rail portion  26  via the rail docking assembly  44 . A first bracket  46  attached to the rail panel assembly  36  is connected to the second bracket  48  attached to the fixed rail portion  26  via fasteners  58 . In a second configuration or erected configuration the rail panel assembly  36  is decoupled with the fixed rail portion  26  and attached to the access walkway assembly  24  along the perimeter of the walkway near the rear portion of the cab. The steps involved in switching from the first configuration to the second configuration is described below. 
         [0034]    As illustrated in  FIG. 1 , the load-body  18  is raised and locked in the elevated position. The operator unlocks the second fixed rail portion  66  with the access walkway  24  and rotates the second fixed rail portion  66  about the axis of the hinges  62  to about 45 degrees, to align it about the external contour of walkway access  24 . The operator then locks the position of the second fixed rail portion  66  to the access walkway  24 . The first rail panel assembly  68  is decoupled with the first fixed rail portions  64 , by unfastening fasteners  58 , and then the rail panel assembly  68  may be lifted and placed at the rear side of the operator station  22 , such that the engagement portion  40  of the leg member  38  of the first rail panel assembly  68  is seated in receptacle member  61  of the receiving portions  60  of the access walkway assembly  24 , as shown in  FIG. 4 . The rail panel assembly  68  would be locked into position, as the leg members  38  are slid into the flange portions  82  of the c-shaped receptacle  61 , until the tab member on the leg member  38  butt against the flange of the receptacle  61 . In the locked position, the engagement portion  40  of the leg member is secured within the flanges of the c-shaped receptacle  61 . The operator then removes the fasteners  58  to decouple the second rail panel assembly  70  from the second fixed rail portion  66 . The second rail panel assembly  70  may be lifted manually and placed at the rear side of the operator station  22 , such that the engagement portion  40  of the leg member  38  of the second rail panel assembly  70  is seated in receptacle member  61  of the receiving portions  60  of the walkway assembly  24 . Referring to  FIG. 4 , the fasteners  58  are coupled to the second bracket  48  of the first fixed rail portion  26 , such that the fasteners are stored. Then the operator unfastens the fasteners  58  that decouples the second rail panel assembly  70  to the second fixed rail portion  68 , lifts the second rail panel assembly  70  and places it in the rear side of the operator station  22 , such that the engagement portion  40  of the leg member  38  of the second rail panel assembly  70  is seated in receiving portions  60  of the access walkway assembly  24 . The fasteners  58  are coupled to the second bracket  48  of second fixed rail portion  70 , such that the fasteners are stored. The support members  74  along with the dual bar members  75  assist in interconnecting the second rail panel assembly  70  to the first rail panel assembly  68 , and the first rail panel assembly  68  with the second fixed rail portion  66 . 
         [0035]    To change from the second or erected configuration back to the stored or first configuration of the guardrail system  23 , the steps explained above should be performed in the reverse order. This gives a great flexibility to an operator to quickly couple and decouple the rail panel assemblies with the fixed rail portions using the specially designed rail docking assembly  44 . The rail docking assembly  44  described here can be used with 
         [0036]    While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.