Patent Publication Number: US-9410330-B2

Title: Mobile scaffolding units with extendible gantry platform and methods of using same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of commonly owned U.S. patent application Ser. No. 13/188,336, filed on Jul. 21, 2011 (now U.S. Pat. No. 8,800,717), which is a continuation-in-part (CIP) of U.S. patent application Ser. No. 13/037,745 filed on Mar. 1, 2011 (now abandoned), and claims domestic priority benefits under 35 USC §119(e) from U.S. Provisional Patent Application Ser. No. 61/400,419 filed on Jul. 28, 2010, the entire contents of each such prior filed application being expressly incorporated hereinto by reference. 
    
    
     FIELD 
     The disclosed embodiments herein relate to mobile devices, specifically motorized vehicles, that are adapted to support and facilitate operator activities including, but not limited to, trimming vegetation adjacent to a roadway. 
     BACKGROUND 
     As should be apparent to those skilled in the art, local, state and federal agencies are responsible for trimming roadside flora to keep vegetation from encroaching upon a roadway and, thereby, interfering with passability of the roadway. Presently, when highway workers are tasked with clearing roadside vegetation, they typically rely upon a vehicle with a crane, boom, or similar apparatus so that workers may reach vegetation at specific heights above the road surface. 
     In one known example, a vehicle with a workman&#39;s bucket connected to an extendible arm or boom (colloquially known as a “bucket truck” in art parlance) assists with clearing vegetation above a height that is not otherwise easily accessible from ground level. A disadvantage with this approach lies in the fact that applicable safety guidelines for operation of such vehicles requires that the vehicle be secured before the boom with an operator-occupied bucket may be deployed. Moreover, in order to move the vehicle from one location to another along the roadway, applicable safety regulations require that the operator must dismount physically from the bucket and/or the bucket must be physically secured in a lowered position. In order to secure the vehicle, the vehicle must be stopped so that the wheels can be secured (e.g., by placement of suitable chocks to prevent inadvertent rolling movement). In addition, pontoons are often extended laterally from the body of the vehicle to provide lateral support and prevent tipping while the boom is manipulated by the operator who occupies the bucket. 
     While this method has proven effective, one significant drawback with it is that the vehicle must be secured periodically at relatively short distance intervals along a roadway to assure that the workers are able to cut the vegetation safely. Moreover, as noted above, the operator must physically dismount from the bucket and/or the bucket must be physically secured in a lowered position before the vehicle is able to move to another location along the roadway. As should be apparent to those skilled in the art, this continual periodic stopping and securing of the vehicle from one location to another along a roadway adds considerably to the time needed to clear vegetation adjacent to the roadway. 
     A need therefore exists for a mobile unit that would reduce the total time (and hence cost) required for clearing vegetation adjacent to and above a road surface. It is towards fulfilling such need that the present invention is directed. 
     SUMMARY OF EXEMPLARY EMBODIMENTS 
     According to some embodiments, mobile scaffolding units are provided which comprise a vehicle for movement across ground surface, a stationary platform rigidly fixed to the vehicle at a predetermined immovable height above the ground surface, and a gantry platform operatively connected to the stationary platform for movements between a retracted position where the gantry platform is nested adjacent to the stationary platform, and an extended position wherein the gantry platform extends laterally outwardly from one or another lateral side of the stationary platform to provide an operator on the gantry platform an extended horizontal reach laterally from the vehicle. 
     According to some embodiments, the gantry platform is moveable between a first extended position where the gantry platform extends outwardly from one side of the stationary platform and a second extended position where the gantry platform extends outwardly from an opposite side of the stationary platform. 
     The gantry platform may comprise a gantry guard rail which is removably attached to the gantry platform. According to such an embodiment, the gantry guard rail can be removed when the gantry platform is in the first extended position thereof so as to allow the gantry platform to thereafter be moved from the first extended position to the second extended position thereof. The gantry guard rail can thus be reattached to the gantry platform when in the second position as a mirror image of the gantry guard rail attached to the gantry platform when the gantry platform is in the first extended position thereof. 
     Some embodiments of the invention will include the gantry platform being operatively connected to the stationary platform so as to be cantilever supported thereby when the gantry platform is in one of the first or second extended positions thereof. As such, weight applied to the gantry platform when in the first or second extended positions applies a bending movement to the rearward portion of the gantry platform thereby frictionally locking the position of the gantry platform against movement toward the retracted position thereof. 
     A slide rail assembly may be provided in other embodiments of the invention so as to operatively connect the gantry platform for reciprocal rectilinear sliding movements between the retracted and extended positions relative to the stationary platform. The slide rail assembly may comprise a pair of slide rail members rigidly connected to the stationary platform, and a pair of support frame members associated with the gantry platform which are slidably received by the slide rail members. Each of the slide rail members may comprise a bearing member which in certain preferred embodiments is formed of a solid polymeric bearing material. 
     In use, an operator may be provided with extended lateral reach toward a work zone by providing a mobile scaffolding unit according to embodiments of this invention. The gantry platform of the mobile scaffolding unit may thus be moved from the retracted position to the extended position thereof so the gantry platform extends laterally of the vehicle toward the work zone. The mobile scaffolding unit can thus be positioned adjacent to one area of the work zone to thereby allow the operator to work therein. Extension of the gantry platform may be performed prior to or after positioning of the vehicle relative to the work zone. Once an operator has completed the tasks in one area of the work zone, the mobile scaffolding unit can be repositioned to another area of the work zone without operator dismount from the gantry platform. 
     These and other aspects of the present invention will become more clear after careful consideration is given to the following detailed description of a presently preferred exemplary embodiment thereof. 
    
    
     
       BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS 
       The disclosed embodiments of the present invention will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative embodiments in conjunction with the drawings of which: 
         FIG. 1  is a top left front perspective view of a mobile scaffolding unit according to one embodiment of the present invention depicted in an environment of use to assist an operator with trimming of roadside vegetation; 
         FIG. 2  is a front elevational view of the mobile scaffolding unit; 
         FIG. 3  is a partial left side elevational view of the mobile scaffolding unit; 
         FIG. 4  is a left rear perspective view of the mobile scaffolding unit depicted in  FIG. 1  but showing the gantry platform thereof extended from an opposite side of the stationary platform; 
         FIG. 5  is a top right perspective view from the rear of the scaffolding assembly disassociated from a vehicle to which it is adapted to be attached; 
         FIG. 6  is a top right perspective view from the front of the scaffolding assembly shown in  FIG. 5 ; 
         FIG. 7  is another top right perspective view from the rear of the scaffolding assembly shown in  FIG. 5 ; 
         FIG. 8  is a top plan view of the scaffolding assembly shown in  FIG. 5 ; 
         FIG. 9  is a partial bottom right perspective view from the front of the scaffolding assembly shown in  FIG. 5 ; 
         FIG. 10  is a simplified top rear perspective view of the frame members forming the stationary platform and the moveable gantry platform and their operative interconnection via the slide rail assembly; 
         FIG. 11  is a partial cross-sectional view showing the slide and bearing rails of the slide rail assembly which interconnects the stationary platform and the moveable gantry platform as taken along lines  11 - 11  therein; and 
         FIGS. 12-17  depict a sequence for repositioning the gantry platform and the associated safety railings from one side of the stationary platform to the other. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-4  are various views of one contemplated embodiment of a mobile scaffolding unit  10  according to a presently preferred embodiment of the present invention. In general, the mobile scaffolding unit  10  according to the embodiment depicted in  FIGS. 1-4  will be comprised of a scaffolding unit SU that is fixed to and carried by a suitable motorized vehicle MV. In the embodiment depicted, the motorized vehicle MV just happens to be shown in the form of a conventional wheeled truck, however, any other suitable wheel- or track-equipped vehicle that can be directionally controlled by an operator for movement over the roadway RW or other ground surfaces may be employed. 
     The scaffolding unit SU is generally comprised of a stationary platform  20  which is immovably fixed to the motorized vehicle MV (e.g., the vehicle chassis VC) and a movable gantry platform  50  which is connected to the stationary platform  20  for relative rectilinear slideable movements. As will be described in greater detail below, such slideable movements allow the gantry platform  50  to be extended laterally relative to the stationary platform  20  so it can be extended from one or another side thereof. The cross-vehicle dimension of the gantry platform  50  is also such that it can assume a retracted position subjacently to stationary platform  20 . In such a retracted position, the gantry platform  50  will not extend laterally beyond the stationary platform  20  so the mobile scaffolding unit  10  can proceed along the roadway RW unimpeded. 
     In connection with the description of the present invention, the mobile scaffolding unit  10 , at least in one contemplated environment for use, is intended to assist with manipulation, specifically the cutting and removal, of vegetation V adjacent to a roadway RW, particularly vegetation that is at a substantial height above the roadway RW as is schematically depicted in  FIG. 1 . Vegetation V is intended to encompass trees, vines, bushes, and large shrubs, among other things, as should be apparent to those skilled in the art. 
     As is schematically depicted in  FIG. 1 , an operator OP can be physically supported by the gantry platform  50  and manipulate a boom saw BS so as to trim vegetation V (e.g., tree limbs) to a desired height above and a desired distance laterally of the roadway RW so as to meet appropriate governmental standards. Once all such vegetation V has been trimmed appropriately, the mobile scaffolding unit  10  can be repositioned along the roadway RW without requiring the operator OP to dismount from the gantry platform  50 . This continual rolling movement of the mobile scaffolding unit  10  provided by the motorized vehicle and the scaffolding unit SU without the requirement of operator dismount will thus translate into a significantly faster removal of vegetation V from alongside the roadway RW. 
     Accompanying  FIGS. 5-11  depict the structures of the scaffolding unit in greater detail. In this regard, it will be observed that the stationary platform  20  is comprised of opposed pairs of perimeter frame members  22 ,  24  which define a generally rectangular platform area  25 . Cross-support frame members  26  span the distance between the lateral frame members  24  so as to support a suitable platform deck  28  (e.g., one or more expanded metal decking sheet) over the platform area  25 . The platform deck  28  is recessed somewhat below the top edges of the perimeter frame members  22 ,  24  so as to provide a toe-stop region  28   a  for an operator supported on the stationary platform  20 . 
     The perimeter frame members are rigidly supported at a desired fixed height above the motorized vehicle MV by means of forward support columns  30  and a transverse upper support beam  32  which spans the support columns  30  for rigidly supporting a forward portion of the stationary platform  20 . A respective pair of ladder supports  34  which include transverse ladder steps  34   a  are rigidly connected to the lateral perimeter frame members  24  so as to support a rearward portion of the stationary platform  20 . The fixed ladder steps  34   a  of the ladder supports  34  will thus allow the operator OP to climb onto the rear portion of the stationary platform  20 . The lower ends of the ladder supports  34  are spanned by a pair of cross-support beams  36  having spacer beams  36   a  fixed therebetween. The cross-support beams  36  are thus in turn rigidly fixed to the vehicle chassis VC to provide rearward support for the elevated stationary platform  20 . 
     The gantry platform  50 , like the stationary platform is constructed of opposed pairs of spaced-apart perimeter frame members  52 ,  54  joined to one another to form a generally rectangular gantry platform area  55 . Cross-support frame members  56  span the distance between the lateral frame members  54  so as to support a suitable gantry platform deck  58  (e.g., one or more expanded metal decking sheet) over the platform area  55 . 
     As is perhaps best seen from  FIGS. 10 and 11  which omit some structural elements for clarity of presentation, the stationary platform  20  and the gantry platform  50  are connected to one another by means of slide rail assembly comprised of a pair of spaced-apart C-shaped slide rails  60  transversely and rigidly fixed to the frame members  24  so as to be parallel to the frame members  22 . Each of the slide rails  60  in turn contains a solid C-shaped bearing  62 , e.g., formed of a polymeric material such as ultra high density polyethylene. Lateral edge regions of the support frame members  52  are thus received by a respective one of the bearings  62  associated with the slide rails  60  so as to allow for reciprocal rectilinear movements (arrow A 1  in  FIG. 10 ) of the frame members  62  relative to the fixed-position slide rails  60 . 
     The slideable and telescopic coupling of the frame members  52  and the bearings  62  of the slide rails  60  allow the entire gantry platform  50  to be moved reciprocally relative to the fixed-position stationary platform  20  between a retracted position (in which the entire gantry platform  50  is subjacently nested within the parametrical boundary of the stationary platform  20 ) and extended positions (wherein a portion of the gantry platform  50  is extended outwardly from one or another side of the stationary platform  20 ). The extended positions of the gantry platform  50  outwardly relative to each side of the stationary platform  20  are shown in solid and dashed lines in  FIG. 10 , respectively. 
     A stop post  64  (see  FIG. 11 ) is rigidly carried by each of the frame members  52  which contacts the lateral frame members  24  so as to limit the amount by which the gantry platform  50  can be extended outwardly relative to the stationary platform  20 . Preferably, the stop posts  64  are positioned approximately midway of its respective frame member  52  so as to limit the extensibility of the gantry platform  50  to approximately half the length of the frame members  52 . 
     It will be understood that the gantry platform  50  is supported in a cantilever manner when in its extended position by virtue of a rearward portion of the frame members  52  being slidably received by the bearings  62  of the slide rails  60  and a forward portion of the frame members  52  being extended outwardly from the lateral side of the stationary platform  20 . Thus, the weight of an operator OP on the gantry platform  50  when in its extended position will apply a transverse force thereto. Such a transversely applied force will in turn exert a bending moment onto the support frame members  52 . Such a bending moment will thereby frictionally lock the position of the frame members  52  with respect to the bearings  62  of the slide rails  60  thereby precluding sliding movement of the gantry platform  50  when an operator OP is positioned on the platform area  55 . Once the operator OP has dismounted the gantry platform  50 , however, the force due to such operator weight will in turn remove the cantilever bending moment that was previously applied to the frame members  52 . As such, the frame members  52  can thereafter be freely slid relative to the bearings  62  of the slide rails  60  (e.g., so as to slidably move the gantry platform  50  to its retracted position relative to the stationary platform  20  or extend the opposite end of the gantry platform  50  outwardly from the other side of the stationary platform  20 ). 
     The stationary and gantry platforms  20  and  50 , respectively, are provided with a guard rail assembly  70  so as to provide a safety barrier for the operator OP when positioned thereon. In preferred embodiments, the guard rail assembly  70  is comprised of a number of removable guard rail members which in turn can be repositioned when the gantry platform  50  is moved from an extended position on one side of the stationary platform to an extended position on the other side of the stationary platform. Accompanying  FIGS. 12-17  depict one possible sequence of operation whereby the extension of the gantry platform  50  can be repositioned from one side to another of the stationary platform  20 . 
     Specifically, as shown in  FIG. 12 , the gantry platform  50  includes a number of guard rail sockets  59  for removably receiving a respective lower end of a vertical post  72  associated with the gantry guard rail member  74 . The horizontal rails  76  are thus fashioned in a manner that bounds the forward and lateral edges of the gantry platform  50  when in its extended position. It will be observed that a kick plate  78  is also provided at the lower region of the horizontal rails  76  to provide additional safety for the operator OP. 
     If the gantry platform  50  is only desired to be moved to its retracted position then the gantry guard rail member  74  does not need to be removed as the posts  72  would then abut against the frame member  24 . However, if it is desired to move the gantry platform  50  from an extended position whereby it extends outwardly from one side of the stationary platform  20  to another extended position whereby it extends outwardly from the opposite side of the platform  20 , then the posts  72  can be removed from their respective sockets  59  to allow the entire gantry guard rail member  74  to be physically separated from the gantry platform  50  (arrow A 2 ). This will in turn allow the gantry platform  50  to be slidably moved (arrow A 3 ) to an opposite extended position as depicted in  FIG. 13 . Once the gantry platform  50  has been moved to the opposite extended position, the guard rail member  74  may be reinstalled (arrow A 4 ) into the now exposed sockets  59  positioned along the opposite one of the frame members  54  to achieve the configuration shown by  FIG. 14 . 
     The stationary platform guardrail members  80 ,  82  and  84  may then be repositioned as shown by  FIGS. 15-17 . Specifically, each of the guardrail members  80 ,  90  and  100  includes respective vertical posts  82 ,  92 , and  102  which are removably received within a socket  40  associated with the stationary platform  20 . The guardrail members  80 ,  90  and  100  also include horizontal rails  86 ,  96  and  106  respectively, so each defines a substantially planar guard rail. Each of the guardrail members  80 ,  90  and  100  may thus be separated from the stationary platform by physically removing the posts  82 ,  92 , and  102  (arrows A 5 ) from a respective one of the sockets  40 . 
     While physically removed, the guardrail members  80 ,  90  and  100  may be reversed so as to be positioned in mirror image arrangement as shown by  FIG. 16 . The posts  82 ,  92 , and  102  may then be received by a respective one of the sockets  40  (arrows A 6 ) so as to assume the position as shown in  FIG. 17 . Following the repositioning of the guardrail assembly  70  as discussed above, the operator OP may again mount the platforms  20 ,  50 , e.g., by climbing the steps  34   a  of a respective one of the ladder support  34  depending on the extended position of the gantry platform  50  relative to the stationary platform  20 . 
     As will be observed, a flexible safety guard  88  formed of a suitable chain, cable, rope or the like spans the distance between the guardrail member  80  and the fixed-position rear guard rail member  110  (comprised of vertical posts  112  and horizontal rails  116 ) so as to close the access space therebetween. A fixed position U-shaped forward guardrail member  120  (comprised of vertical posts  122  and horizontal rails  126 ) may also be provided at a forward end of the stationary platform  20 . 
     While the present invention is described in connection with the trimming of trees and like vegetation V adjacent to a roadway RW, the present invention may be employed for many other types of operations. For example, it is contemplated that the motorized vehicle MV of the present invention may be employed in circumstances where the walls of a tunnel need to be cleaned. Alternatively, the vehicle MV of the present invention may be employed where a vertical surface needs to be painted or otherwise refurbished. In still a further embodiment, the vehicle MV might be employed by those responsible for changing light bulbs in roadside lamps or even fixtures on buildings. For example, it is contemplated that the vehicle VM of the present invention might be employed to assist with changing light bulbs in the canopies that extend over the gas pumps at a gas station. The sheer magnitude of the possible applications of the present invention discourages the presentation of an exhaustive list of potential uses. It is to be understood, however, that the present invention is not limited solely to the cutting and trimming of roadside vegetation V. To the contrary, as should be apparent to those skilled in the art, any number of possible uses may be found for the present invention. 
     It is also noted that the present invention has been discussed in connection with the cutting and trimming of vegetation V adjacent to a roadway RW. However, as should be immediately apparent, the present invention may be employed off-road as well. Specifically, the scope of the present invention is intended to encompass both on-road and off-road environments. 
     In addition, the specific reference to any single aspect of the present invention is not intended to be limiting of the invention. Certain aspects of the invention may have been discussed in connection with “the present invention” merely to simplify the discussion. In other words, reference to “the present invention” in one or more contexts above is not intended to be limiting thereof. 
     The particular motorized vehicle MV to which the scaffolding unit SU is attached is not critical. Thus, a wide variety of electric and internal combustion engine vehicles can be contemplated to provide the mobile scaffolding unit  10  with self-propelled functionality, i.e., so the scaffolding unit SU can be moved periodically over ground surface. Thus, any variety of wheeled or tracked vehicles is currently contemplated for use in the present invention. 
     Therefore, while the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope thereof.