Patent Publication Number: US-2005126051-A1

Title: Material pusher with improved structure

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority from and benefit of the filing date of U.S. provisional application Ser. No. 60/529,801 filed Dec. 16, 2003 and U.S. provisional application Ser. No. 60/578,169 filed Jun. 9, 2004. 
    
    
     BACKGROUND  
      Pusher devices for clearing snow and other materials (e.g., manure, mud, etc.) from a roadway, runway, parking lot or-other surface are well-known and in widespread use. These known devices include a blade that is fixed or foldable and some means for operatively and temporarily securing the blade to a wheel-loader, skid-steer tractor, wheel-loader backhoe, or other machine used to move the pusher.  
      Known pushers are deficient for a wide variety of reasons. In many cases, the pushers have a structure that is difficult to manufacture, high-weight, and prone to damage during use, with weak spots and stress-concentration zones. Known pushers have not used vertical ribs cut from plates to tie the horizontal structural members together. Known pushers also have not used such vertical ribs to define the coupler portion of the pusher and, instead, have used posts that are merely connected to the pusher without being integrated into the overall structure.  
      Some pushers use bolts to connect the skid-shoe assemblies to the blade without providing any shear protection for the bolts. Many known pushes include deficient sidewall support gussets that trap material and/or that are not robustly attached to the sidewall and/or blade. Known pushers include coupler portions defined from hollow post structures that are not integrated into the overall structure of the pusher and that decrease visibility.  
      Known pushers are prone to tip rearward when not in use (e.g., during a decoupling operation) which renders storage unsafe and unsightly and that complicates re-coupling.  
      Conventional pusher devices also are designed for the wiper to contact and clear the underlying surface even when the pusher is not properly oriented on the surface, which leads to uneven wear of the skid-shoe assemblies without any indication to the operator that the pusher is not properly oriented.  
      Known folding pushers have been deemed suboptimal for a wide variety of reasons. Some require complex hydraulic systems for the folding and/or locking operations. Others rely on locking mechanisms that are overly complex or that are prone to damage and/or loss of components.  
     SUMMARY  
      In accordance with the present development, a pusher includes: a blade including a front surface for moving material and an opposite rear surface, and upper and lower edges; a wiper secured to the lower edge of the blade; left and right sidewalls connected to opposite sides of the blade, said sidewalls each arranged transverse to the blade; left and right skid-shoe assemblies connected respectively to the left and right sidewalls, said left and right skid-shoe assemblies cooperating with each other to slidably support the blade above a surface to be cleared; a plurality of cross-supports connected to the rear surface of the blade and extending between the left and right sidewalls; a coupler structure comprising: (i) a plurality of coupler ribs that are connected to and extend between at least some of the cross-supports; and, (ii) a pick-up location adapted to be engaged by an associated pusher-moving machine for operative connection of the blade to the associated pusher-moving machine.  
      In accordance with another aspect of the present development, a fixed-angle pusher for moving material laterally when said pusher is moved forwardly in an operative direction of movement comprises: a blade including a front surface for moving material and an opposite rear surface, and upper and lower edges; a wiper secured to the lower edge of the blade; left and right sidewalls connected to opposite sides of the blade and arranged parallel to the direction of operative movement, said sidewalls each arranged transverse to the blade, wherein said second sidewall trails said first sidewall with respect to the direction of operative movement, and wherein said first sidewall projects outwardly from said front surface of said blade more than said second sidewall projects outwardly from said front surface of said blade; left and right skid-shoe assemblies connected respectively to the left and right sidewalls, said left and right skid-shoe assemblies cooperating with each other to slidably support the blade above a surface to be cleared; a plurality of cross-supports connected to the rear surface of the blade and extending between the left and right sidewalls; a coupler structure comprising: (i) at least one wedge-shaped coupler plate connected to and projecting outwardly from one of said cross-supports; (ii) a plurality of first and second coupler ribs that are connected to said at least one wedge-shaped coupler plate, said first and second coupler ribs defining a pick-up location adapted to be engaged by an associated pusher-moving machine for operative connection of the blade to the associated pusher-moving machine, wherein a distance between said pick-up location and said blade decreases as a distance between said pick-up location and said second sidewall decreases.  
      In accordance with another aspect of the present development, a pusher comprises: a blade including a front surface for moving material and an opposite rear surface, and upper and lower edges; a wiper secured to the lower edge of the blade; left and right sidewalls connected to opposite sides of the blade, said sidewalls each arranged transverse to the blade; left and right skid-shoe assemblies connected respectively to the left and right sidewalls, said left and right skid-shoe assemblies cooperating with each other to slidably support the blade above a surface to be cleared; a plurality of cross-supports connected to the rear surface of the blade and extending between the left and right sidewalls; a coupler structure comprising: (i) a plurality of coupler ribs that are connected to and extend between at least two of the cross-supports; and, (ii) a pick-up location adapted to be engaged by an associated pusher-moving machine for operative connection of the blade to the associated pusher-moving machine, said pick-up location comprising an open slot adapted to receive a bucket lip.  
      In accordance with a further aspect of the present development, a pusher comprises: a blade including a front surface for moving material and an opposite rear surface, and upper and lower edges; a wiper secured adjacent the lower edge of the blade; left and right sidewalls connected to opposite sides of the blade, said sidewalls each arranged transverse to the blade; left and right skid-shoe assemblies connected respectively to the left and right sidewalls, said left and right skid-shoe assemblies cooperating with each other to slidably support the blade above a surface to be cleared; a coupler structure projecting outwardly from the rear surface of the blade and defining a pick-up location adapted to be engaged by an associated pusher-moving machine for operative connection of the blade to the associated pusher-moving machine; and, at least one chain-engaging aperture defined in each of the left and right sidewalls, said at least one chain-engaging aperture of each sidewall comprising a first region adapted to receive and allow passage of an associated chain and a second region adapted to engage and retain the associated chain for selectively fixedly securing the pusher to an associated pusher-moving machine.  
      In accordance with another aspect of the present development, a pusher comprises: a blade including a front surface for moving material and an opposite rear surface, and upper and lower edges; a wiper secured adjacent the lower edge of the blade; left and right sidewalls connected to opposite sides of the blade; left and right skid-shoe assemblies connected respectively to the left and right sidewalls, said left and right skid-shoe assemblies cooperating with each other to slidably support the blade above a surface to be cleared; a coupler structure operatively connected to the blade and defining a pick-up location adapted to be engaged by an associated pusher-moving machine for operative connection of the blade to the associated pusher-moving machine; and, wherein the left and right sidewalls comprise respective left and right sidewall flanges projecting outwardly therefrom and wherein said left and right skid-shoe assemblies are abutted with the left and right sidewall flanges and are connected to the left and right sidewalls by bolts, respectively, so that at least some impact forces on said left and right skid-shoe assemblies are transferred to said left and right sidewalls through said left and right sidewall flanges, respectively, to protect said bolts from shearing forces.  
      In accordance with a further aspect of the present development, a pusher comprises: a blade including a front surface for moving material and an opposite rear surface, and upper and lower edges; a wiper secured adjacent the lower edge of the blade; left and right sidewalls connected to opposite sides of the blade, said sidewalls each arranged transverse to the blade; left and right skid-shoe assemblies connected respectively to the left and right sidewalls, said left and right skid-shoe assemblies cooperating with each other to slidably support the blade above a surface to be cleared; a coupler structure operatively connected to the blade and defining a pick-up location adapted to be engaged by an associated pusher-moving machine for operative connection of the blade to the associated pusher-moving machine; wherein said left and right skid-shoe assemblies each comprise a wear-shoe having a primary portion that slidably supports the blade above a surface to be cleared, and wherein the sidewalls comprise upper edges that are parallel to the primary wear-shoe portions of the left and right skid-shoe assemblies, respectively, to provide a visual indication to an operator as to the orientation of the primary wear-shoe portions.  
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
      The development comprises various structures and components and arrangements of same, preferred embodiments of which are disclosed with reference to the accompanying drawings wherein:  
       FIG. 1  is a rear isometric view of a material pusher formed in accordance with the present development;  
       FIG. 2  is a front isometric view of the pusher shown in  FIG. 1 ;  
       FIGS. 3 and 4  are respective front and rear elevational views of the pusher shown in  FIG. 1 ;  
       FIGS. 5 and 6  are respective top and bottom plan views of the pusher shown in  FIG. 1 ;  
       FIG. 7  is a right side elevational view of the pusher shown in  FIG. 1  (the left side elevational view is substantially identical);  
       FIGS. 7A and 7B  illustrate operation and use of the chain-engaging apertures;  
       FIG. 8  is a sectional view taken along line  8 - 8  of  FIG. 4  and showing the pusher resting on a surface to be cleaned thereby;  
       FIG. 9  is a right side elevational view that is similar to  FIG. 7  that shows the pusher located in an undesired position that renders the pusher less effective;  
       FIG. 10  is an exploded isometric view of the left and right skid-shoe assemblies of the pusher of  FIG. 1 , and shows connection of an adapter bracket to same to allow for use of the skid-shoe assemblies with a popular conventional pusher device;  
       FIGS. 11A and 11B  are rear and front isometric views of a skid-steer version of a pusher formed in accordance with the present development;  
       FIG. 11C  is an isometric view of a pusher including a JRB-style female coupler portion for mating with a JRB-style male coupler portion;  
       FIG. 12  is a rear isometric view of an offset pusher structured in accordance with the present development;  
       FIG. 13  is a rear isometric view from above of a folding pusher formed in accordance with the present development, in its opened configuration;  
       FIG. 14  is a front isometric view of the folding pusher shown in  FIG. 13  in its opened configuration;  
       FIG. 15  is an isometric view of the pusher of  FIG. 13  with one blade section in a folded and locked position, and the other blade section in the open and locked position;  
       FIG. 16 , shows the pusher of  FIG. 13  in its fully folded and locked configuration;  
       FIGS. 17 and 18  are enlarged views of the right one of the two fold-locks of the pusher shown in  FIG. 13 ;  
       FIG. 19  shows the left fold-lock;  
       FIG. 20  shows another folding pusher formed in accordance with the present development;  
       FIG. 21  is an enlarged view of one of the two open-locks for the pusher of  FIG. 20 ;  
       FIG. 22  is an enlarged view of the fold-lock of the pusher shown in  FIG. 20 ;  
       FIGS. 23-25  show the sidewall gusset structure for the pushers of  FIGS. 1-22 ;  
       FIGS. 26 and 27  are front and rear isometric views of a fixed-angle pusher formed in accordance with the present development;  
       FIG. 28  is a top plan view of the fixed-angle pusher of  FIGS. 26 and 27 .  
    
    
     DETAILED DESCRIPTION  
       FIGS. 1-7  illustrate a pusher P formed in accordance with the present development. Unless otherwise specified, all components of the pusher P are defined from a suitable metal such as steel and/or various alloys thereof. The pusher comprises a body B and a coupling structure C connected to the body. The body B comprises a main blade portion D having a front or forwardly facing operative pushing surface DF that is preferably concavely curved and an opposite rear or rearward facing surface DR to which the coupling structure C is connected by welding or other means such as bolts or other fasteners. Blade D is formed by one or more curved plates.  
      First and second (left and right) sidewalls S 1 ,S 2  are located at opposite lateral ends of the blade D and project forwardly outward from the front surface DF thereof and also project in the rearward direction outwardly from rear surface DR of blade D. In the illustrated example, the sidewalls S 1 ,S 2  are parallel to each other and are vertically oriented, assuming the pusher P is operatively resting on a horizontal surface. The blade also D includes upper and lower edges DU,DL that extend laterally between the sidewalls parallel to each other.  
      The first and second sidewalls S 1 ,S 2  include respective first and second (left and right) removable skid-shoe assemblies H 1 ,H 2  that support the pusher P for sliding movement on a surface Z ( FIG. 7 ) to be cleared, such as a parking lot, airport runway, etc., with the lower edge DL of the blade adjacent but not in contact with the surface. A wiper W such as a rubber strip or other durable and resilient means (e.g., a spring-loaded metal blade) is secured adjacent the blade lower edge DL and is intended to contact the surface Z being cleared by the pusher P. In the illustrated embodiment, the wiper W is coextensive with the blade lower edge DL and, thus, extends substantially from sidewall S 1  to sidewall S 2  to the fullest extent possible as limited by the skid shoes H 1 ,H 2 . The wiper W is secured using a metal facing strip WS and a plurality of bolts T advanced into the blade D through both the strip WS and wiper W. The wiper W is reversible when worn to lengthen its useful life.  
      First and second gussets G 1 ,G 2  ( FIGS. 2, 3 ) are respectively used to reinforce the connection of the sidewalls S 1 ,S 2  to the blade. The gussets are shaped for maximum strength, ease of assembly, weight savings and to prevent accumulation of snow or other material between themselves and the blade D and/or sidewalls S 1 ,S 2  as described in further detail below.  
      The rear surface DR of the blade D is reinforced with a plurality of parallel cross-supports such as a first (top), second (middle) and third (lower) cross-supports X 1 ,X 2 ,X 3  (see e.g.,  FIGS. 1, 8 ). The first cross-support X 1  is shown as a rectangular tube member that is welded to the rear surface DR or blade D adjacent the upper edge DU and coextensive therewith between sidewalls S 1 ,S 2 . The second cross-support X 2  is shown as an L-shaped angle member welded to the rear face DR of blade D between the upper and lower edges DU,DL and that extends continuously to and between the sidewalls S 1 ,S 2 . The third cross-support X 3  is shown as a plate stock member that is located adjacent the blade lower edge DL and that is coextensive therewith between the sidewalls. The cross-supports X 1 ,X 2 ,X 3  are preferably parallel with each other and with the upper and lower blade edges DU,DL. The rear surface DR of the blade D is also reinforced with a first set of vertical reinforcement ribs R 1  defined from plate steel sections that are welded to and extend vertically between the first and second cross-members X 1 ,X 2  for structural integration of the cross-members X 1 ,X 2 . A second set of vertical reinforcement ribs comprises a plurality vertical ribs R 2  defined from plate steel are welded to and extend between the second and third cross-supports X 2 ,X 3  and provide additional stiffness to the lower edge DL of the blade D and to tie the cross-members X 2 ,X 3  together.  
      With particular reference now to  FIGS. 1 and 7 , the coupler structure C of the pusher P is used to connect the pusher P operatively to a wheel-loader, skid-steer tractor, wheel-loader backhoe, or other machine used to move the pusher (pusher-moving machine) and comprises a first (upper) set of coupler ribs comprising a plurality of laterally spaced-apart ribs CR 1 ,CR 2 ,CR 3 , each defined from a planar section of steel plate, and each connected to and extending vertically between the first (upper) cross-support X 1  and the second (middle) cross-support X 2 . The upper ribs CR 1 -CR 3  are interconnected by a first cross-bar CB 1  that is spaced outwardly from the rear surface DR of blade D for added strength. The coupler C further comprises a second (lower) set of coupler ribs comprising a plurality of laterally spaced-apart lower ribs CR 1 ′,CR 2 ′,CR 3 ′, each defined from a planar section of steel plate, and each connected to and extending vertically between the central (middle) cross-support X 2  and the third (lower) cross-support X 3 , and that are preferably in alignment with the upper ribs CR 1 ,CR 2 ,CR 3 , respectively. These ribs CR 1 ′-CR 3 ′ are interconnected by a cross-bar CB 1 ′ that is spaced outwardly from the rear surface DR of blade D for added strength. The upper ribs CR 1 -CR 3  and lower ribs CR 1 ′-CR 3 ′ are conformed and arranged relative to each other so that a narrow, laterally-extending open slot L (easily seen in  FIG. 7 ) is defined therebetween and provides a pick-up location for connection of the pusher P to an associated pusher-moving machine. In particular, the slot L is adapted to receive the lower lip of a material-handling bucket connected to a front-end loader, backhoe or other pusher-moving machine so that the loader or other machine can be used to move the pusher P slidably across the surface Z to be cleaned, with the forward face DF of blade D oriented forward in the direction of movement and with the rear face DR oriented toward the pusher-moving machine. In the illustrated embodiment, each upper coupler rib CR 1 ,CR 2 ,CR 3  is defined as a one-piece construction with the respective lower rib CR 1 ′,CR 2 ′,CR 3 ′ from a single steel plate CR that defines a rib slot LR. The ribs slots LR cooperate to define the slot L when aligned with each other. In such case, each coupler rib plate CR extends between and is connected to at least two and preferably all of the first, second and third cross-supports X 1 ,X 2 ,X 3 .  
      Chains are secured between the bucket or other part of the associated pusher-moving machine and the sidewalls S 1 ,S 2  by insertion of the chains into one or more of the chain-engaging apertures N 1 ,N 2 ,N 3  of sidewalls S 1 ,S 2  of pusher. At least some of the coupler rib plates CR define plain apertures N that allow respective chains or chain strands or hooks to pass therethrough to facilitate use of the chains to connect the pusher P to the associated pusher-moving machine. As shown separately in  FIGS. 7A,7B , with reference to the chain-engaging aperture N 1 , each of the chain-engaging apertures N 1 ,N 2 ,N 3  is keyhole-shaped and able to capture the links of a chain CN therein in a secure fashion. Each aperture N 1 ,N 2 ,N 3  is defined by an enlarged portion KE and a narrowed portion KN. An associated conventional link chain CN is able to move freely through the enlarged portion KE ( FIG. 7A ), but the chain CN is unable to pass through the narrowed portion KN and, instead, is captured therein by the sidewall S 1 ,S 2 . Multiple chain-engaging apertures N 1 ,N 2 ,N 3  are preferably defined in each sidewall for two purposes: (i) the varied locations allow for adjustment of chain position; and, (ii) damage to one of the chain-engaging apertures N 1 ,N 2 ,N 3  simply requires that the chain be moved to another, undamaged chain-engaging aperture. Alternatively, each sidewall S 1 ,S 2  can include only a single chain-engaging aperture N 1 ,N 2 ,N 3 .  
      With brief reference to  FIG. 8 , it is preferred that the innermost region of slot L of the coupler C be defined by an insert member L 1  that is wear resistant as compared to the material from which ribs CR 1 -CR 3  and CR 1 ′-CR 3 ′ are defined to prevent undue wear from the lip of the bucket that is received into the slot L. Owing to its rib structure, it can be seen that the coupler structure C is integrated into and forms part of the overall structure of the pusher P for added strength. Loads from exerted on the coupler structure C are transferred to and dispersed throughout the pusher structure owing to the connection between the upper and lower coupler ribs CR 1 -CR 3 , CR 1 ′-CR 3 ′ and the cross-supports X 1 ,X 2  and X 2 ,X 3 , respectively.  
       FIGS. 11A and 11B  show an alternative embodiment of a pusher  100 P that is substantially similar to the pusher P except as otherwise shown and/or described and, as such, the same reference characters are used except for new components. The pusher  100 P differs from the pusher P in that it includes a coupler structure  100 C that comprises a female coupler portion QC of a male/female quick-coupler as the pick-up location instead of the slot L described above for the coupler structure C of pusher P, where the mating male portion (not shown) is pinned-on or otherwise operatively connected to the pusher-moving machine to which the pusher  100 P is to be connected for use. The quick coupler portion QC shown is a conventional female skid-steer quick-coupling portion but can alternatively be defined by any other quick-coupler known in the art. The coupler structure  100 C comprises a plurality of vertical ribs CR 4 ,CR 5 ,CR 6  each defined from steel plate that extend between and that are connected to all of the cross-supports X 1 ,X 2 ,X 3  so as to integrate the coupler structure  100 C into the overall structure of pusher  100 P for added strength. The quick coupler portion QC is connected to the coupler ribs CR 4 ,CR 5 ,CR 6  by welding or by bolts or other fasteners.  
       FIG. 11C  shows an alternative embodiment of a pusher  100 P′ that is substantially similar to the pusher P except as otherwise shown and/or described and, as such, the same reference characters are used except for new components. The pusher  100 P′ differs from the pusher P in that it includes a coupler structure  100 C′ that comprises a female coupler portion QC′ of a male/female quick-coupler as the pick-up location instead of the slot L described above for the coupler structure C of pusher P, where the mating male portion (not shown) is pinned-on or otherwise operatively connected to the pusher-moving machine to which the pusher  100 P′ is to be connected for use. The quick coupler portion QC′ shown is a conventional female JRB-style quick-coupling portion. As such, the coupler structure  100 C′ and quick coupler portion QC′ thereof comprises first and second parallel vertical coupler ribs J 1 ,J 2 , each including a hook and an eye, that cooperate to define the well-known JRB-style female coupler portion. Each coupler rib J 1 ,J 2  is defined from a single steel plate that extends between and is connected to at least two and, preferably, all of the cross-supports X 1 ,X 2 ,X 3  so as to integrate the coupler structure  100 C′ into the overall structure of pusher  100 P′ for added strength.  
       FIG. 12  shows an offset pusher  200 P that is substantially similar to the pusher P except as otherwise shown and/or described and, as such, the same reference characters are used except for new components. The pusher  200 P differs from the pusher P in that it includes a coupler structure  200 C that encompasses the coupler structure C (except for the cross-bars CB 1 ,CB 1 ′), including coupler ribs CR 1 ,CR 2 ,CR 3  and CR 1 ′,CR 2 ′,CR 3 ′ as described above. The coupler structure  200 C further comprises additional coupler ribs CR 0 ,CR 0 ′ and CR 4 ,CR 4 ′ that are identical to the ribs of coupler structure C, but that are located on opposite sides of the coupler structure C. The coupler ribs CR 0  and CR 4  preferably have the same structure ribs CR 1 ,CR 2 ,CR 3  and the ribs CR 0 ′ and CR 4 ′ preferably have the same structure as ribs CR 1 ′,CR 2 ′,CR 3 ′. In the illustrated embodiment, the upper coupler ribs CR 0 ,CR 1 ,CR 2 ,CR 3  are defined as respective one-piece constructions with the lower ribs CR 0 ′,CR 1 ′,CR 2 ′,CR 3 ′, each from a single steel plate CR that defines a rib slot LR. The ribs slots LR cooperate to define the slot L when aligned with each other. In such case, each coupler rib plate CR preferably extends between and is connected to at least two and most preferably all of the first, second and third cross-supports X 1 ,X 2 ,X 3 .  
      The coupler structure  200 C of the pusher  200 P comprises three separate coupler structures, each defined by at least three spaced-apart upper coupler ribs CR 0 ,CR 1 ,CR 2 ,CR 3  and three corresponding lower coupler ribs CR 0 ′,CR 1 ′,CR 2 ′,CR 3 ′. As shown, the coupler structure comprises: (i) a main coupler structure C; (ii) a left coupler structure LC; and, (iii) a right coupler structure RC; each defining its own pick-up location such as a portion of slot L. Each coupler structure C,LC,RC is adapted to be engaged by an associated pusher-moving machine. The coupler structure C allows the pusher  200 P to be symmetrically coupled to the pusher-moving machine; the coupler structure LC allows the pusher  200 P to be coupled to the pusher-moving machine with a right offset relative; and the coupler structure RC allows the pusher  200 P to be coupled to the pusher-moving machine with a left offset. The offset coupling is often desired when the pusher  200 P must be used to clear snow or other material from beneath an overhang that will not accommodate the pusher-moving machine.  
      Referring again to the pusher P shown in  FIGS. 1-9 , the left and right skid-shoe assemblies H 1 ,H 2  are identical to each other and can be interchangeably mounted to either sidewall S 1 ,S 2  as desired using bolts or other fasteners HB. With reference to the shoe assembly H 2  and  FIGS. 1 and 7 , the shoe assemblies H 1 ,H 2  comprise a vertical rib HR and a transverse wear-shoe HS that is welded or otherwise fixedly secured to the rib HR. The wear-shoe HS preferably includes a flat primary (central) portion HS 1  that is adapted to abut a surface Z to be cleared. With particular reference now to  FIG. 7 , the wear-shoe HS comprises upturned ends HS 2 ,HS 3  that facilitate sliding movement of the shoe HS over obstacles of surface Z in forward and reverse directions. The vertical rib. HR includes an upper edge HR 1  that is preferably parallel to the central portion HS 1  of the wear-shoe. The vertical ribs HR of the shoe assemblies H 1 ,H 2  are partially overlapped with the sidewalls S 1 ,S 2  and fastened thereto by bolts or other fasteners. The sidewalls S 1 ,S 2  of the pusher P include respective outwardly projecting flanges SF 1 ,SF 2  (see also  FIG. 3 ) that extend parallel to primary wear-shoe portions HS 1  and that abut the upper edge HR 1  of the shoe assembly rib HR when the skid-shoe assemblies H 1 ,H 2  are operatively secured to the sidewalls S 1 ,S 2 . As such, the bolts HB by which the shoe assemblies H 1 ,H 2  are secured to the sidewalls S 1 ,S 2  are protected from shearing forces that would otherwise act on the bolts HB as the pusher P moves slidably across the surface Z and impacts obstacles, i.e., forces from the shoe assemblies H 1 ,H 2  are transferred to sidewalls S 1 ,S 2  through the ribs HR and flanges SF 1 ,SF 2 , respectively, rather than solely through the bolts HB as could lead to shearing of the bolts. The flanges SF 1 ,SF 2  also add strength and stiffness to the sidewalls S 1 ,S 2  and, to this end, the flanges SF 1 ,SF 2  are preferably defined as rectangular one-piece members that project transversely outward from the sidewalls S 1 ,S 2  a greater extent as compared to the extent with which they abut the sidewalls S 1 ,S 2 , respectively.  
      With reference to  FIGS. 7-9 , it is also preferred that the sidewalls S 1 ,S 2  each include an upper edge SU that is parallel to the primary portion HS 1  of the wear-shoe, i.e., the upper edges SU are horizontal when the pusher P is supported on a horizontal surface Z. As such, for reasons that are important as will become apparent below, the upper edges SU of sidewalls S 1 ,S 2  provide a guide to an operator as to the relationship between the central portion HS 1  of the wear shoe and the surface Z being cleared.  
      It is intended that the central portion HS 1  of each skid shoe assembly H 1 ,H 2  be positioned flat on the surface Z being cleaned as shown in  FIG. 7  to minimize wear and to ensure uniform wear of the shoe components HS thereof. With particular reference now to  FIGS. 8 and 9 , it can be seen that the central portion HS 1  of each shoe assembly H 1 ,H 2  intersects the upturned rear portion HS 3  or otherwise terminates well aft of the lower edge of wiper W in a terminal location HT that is at least vertically aligned with the slot L of the coupler structure C, if not farther rearward. As shown in  FIGS. 11A,11B  the terminal location HT is rearward of the entire coupling structure  100 C. If no upturned surface HS 3  is provided, the terminal location HT is simply the rear edge of the surface HS 1 . In the event an operator improperly orients the pusher P during use by reclining the pusher as shown in  FIG. 9 , the pusher P pivots relative to the surface Z on the shoe terminal location HT so that the wiper W is lifted away from the surface Z being cleared to prevent effective surface clearing. In such case, an operator will immediately realize that he/she has not properly oriented the pusher P when the wiper W fails to clear the surface Z adequately. Conventional pushers allow the wiper to contact the surface being cleared even when the wear-shoe is not positioned flat on the surface. Furthermore, with a pusher P formed in accordance with the present development, the upper edge SU of each sidewall S 1 ,S 2  is parallel to the central portion HS 1  of the wear shoe HS and an operator can thus use the upper edge SU as a visual proxy or guide for the position of the central portion HS 1  of wear shoe HS. In use, an operator will strive to maintain the upper edges SU of sidewalls S 1 ,S 2  parallel to the surface Z being cleared (which is typically in a horizontal orientation when a “flat” horizontal surface is being cleared) which indicates that the central portion HS 1  of each wear shoe HS is flat on the surface Z. It is most preferred that the terminal location HT of the wear-shoes HS be spaced sufficiently from and behind the lowermost edge of wiper W so that if the central shoe portion HS 1  is inclined even 5 degrees or more relative to surface Z, the wiper W will be lifted away from the surface Z a sufficient amount so that snow or other material being cleared will remain on the surface Z and noticed by an operator. Preferably the terminal location HT is positioned at least twelve inches and as much as fifteen inches or more behind the point where the wiper W contacts the surface Z. This structure and relationship also inhibits rearward tipping movement of the pusher P when a bucket lip is withdrawn from slot L during a decoupling operation. Those of ordinary skill in the art will also recognize from  FIGS. 1 and 7  that the shoe assemblies H 1 ,H 2  project rearward from the rear surface DR of blade D a significant distance so as to be visible to an operator during use of the pusher as also facilitates proper orientation during use. It is preferred that the overall rearmost tip of the shoe assemblies H 1 ,H 2  be located at least twenty inches behind the wiper W for this added visibility by an operator. The structure of the skid-shoe assemblies H 1 ,H 2  as just described is complimented by the sidewalls S 1 ,S 2  having respective trailing fins TF 1 ,TF 2  that begin at a point aligned with the innermost region of coupler slot L and that project rearward away from rear surface DR of pusher blade D to a rearward point that is vertically aligned with the coupler slot L as shown in  FIGS. 1 and 7 . In this manner, the skid-shoe assemblies H 1 ,H 2  and sidewalls S 1 ,S 2  approximately correspond in length at the connection thereof.  
      If desired, the skid shoe assemblies H 1 ,H 2  can be used as part of another, conventional pusher as a replacement part by connection respective adapter brackets K 1 ,K 2  thereto as shown in  FIG. 10 . The adapter brackets K 1 ,K 2  are identical, mirror images of each other and each comprise an inner plate Ki, an outer plate Ko and a central spacer plate Kc (see adapter bracket K 2 ). The plates Ki,Ko,Kc are welded together so as to define a slot Ks into which the rib HR of the shoe assembly H 1 ,H 2  is closely and slidably received. The inner plate Ki is conformed and dimensioned to cooperate with the wear shoe portion HS to define a space that receives a pusher sidewall SW (of a competitive or other pusher and shaped differently from sidewalls S 1 ,S 2 ) as shown in broken lines with minimal clearance. The brackets K 1 ,K 2  include elongated mounting holes Km that are easily aligned with holes Kr of the ribs HR so that the bolts Kb are used to fixedly secure the brackets K 1 ,K 2  to the ribs HR. The sidewall SW is bolted to the shoe assemblies H 1 ,H 2  in the same manner as described above in relation to  FIGS. 1-7  (except sidewalls SW do not include the shear-protecting flanges SF 1 ,SF 2 ).  
       FIGS. 13-19  show a folding pusher P′ and/or components thereof formed in accordance with an alternative embodiment of the present development. Except as otherwise shown and/or described, the pusher P′ is identical to the pusher P and, as such, like components share like reference characters. The pusher P′ is defined by dividing the blade D of the non-folding pusher P into three blade sections D 1 ,D 2 ,D 3 . The first (left) section D 1  is bounded by the first sidewall S 1  and a first inner wall V 1   a ; the second (center) section D 2  is bounded by first and second lateral walls V 2   a ,V 2   b ; and, the third (right) section D 3  is bounded by the second sidewall S 2  and a second inner wall V 1   b . The walls V 1   a  and V 2   a  are pivotally interconnected via first hinge HG 1 , and the walls V 1   b  and V 2   b  are pivotally interconnected via second hinge HG 2 .  
      As noted, the blade sections D 1 ,D 2 ,D 3  are defined by dividing the blade D of pusher P into three separate sections. As such, each section comprises the relevant portion of the structure of the blade D described above. Thus, for example, the coupler C (or  100 C) is connected to the second (central) section D 2 . Each section D 1 -D 3  comprises an upper edge DU, a lower edge DL, and the first, second and third cross-supports X 1 ,X 2 ,X 3 , along with ribs R 1 ,R 2  as shown. Because the blade sections D 1 ,D 2 ,D 3  are defined by dividing the blade D of pusher P as described, the wiper W′ ( FIG. 14 ) varies somewhat from wiper W described above in that it is defined by three separate wipers W 1 ,W 2 ,W 3  connected respectively adjacent the lower edges DL of the blade sections D 1 ,D 2 ,D 3  using three separate wiper retaining strips WS 1 ,WS 2 ,WS 3  and bolts T. The three separate wipers W 1 ,W 2 ,W 3  cooperate to define a continuous, substantially uninterrupted wiper W′ that extends from sidewall S 1  to sidewall S 2  when the pusher P′ is in the opened (unfolded) position as shown in  FIGS. 13 and 14 .  
      As shown in  FIGS. 15 and 16 , the hinges HG 1 ,H 2  are structured and located so that the left and right blade sections D 1 ,D 3  pivot forwardly and inward toward each other, in an independent fashion, so that their front faces DF move into opposed facing relation to each other ( FIG. 16 ). During this folding operation, the walls V 1   a ,V 2   a  move from a first position, where they are abutted (or at least closely adjacent) and substantially parallel when the pusher P′ is in the unfolded (opened) operative position, to a second position where they define an obtuse angle having its vertex at hinge HG 1  when pusher P′ is folded or closed. Likewise, during the folding operation, the walls V 1   b ,V 2   b  move from a first position, where they are abutted (or at least closely adjacent) and substantially parallel when the pusher P′ is in the unfolded or opened position, to a second position where they define an obtuse angle having its vertex at hinge HG 2  when pusher P′ is folded. It is also preferred that the blade sections D 1 ,D 3  pivot inwardly toward each other sufficiently so that the sidewalls S 1 ,S 2  and shoes H 1 ,H 2  thereof move close to or into contact with each other. When one ( FIG. 15 ) or both ( FIG. 16 ) of the blade sections D 1 ,D 3  are folded, the pusher P′ has a reduced size as is often deemed desirable for storage or transport or for temporarily reducing its width during use to fit between obstacles.  
      The pusher P′ comprises first and second fold-locks FL 1 ,FL 2  to retain the first and third blade sections D 1 ,D 3 , respectively, in either their opened or closed positions independently from each other. The structure and operation of the fold-locks FL 1 ,FL 2  is easily understood with reference to  FIGS. 17-19 . The fold-lock mechanisms FL 1 ,FL 2  are identical but the components are arranged in a mirror-image fashion.  
      The fold-lock FL 2  is shown in  FIGS. 17 and 18 . There, it can be seen that the second lateral wall V 2   b  of the central blade section D 2  comprises a slot  200 . An arcuate lock bar  202  extends through the slot  200 . An inner end  202   a  of the lock bar  202  is secured to a retainer pin  204  that is, in turn, secured to the second lateral wall V 2   b  (or other portion of central blade section D 2 ) by a yoke structure  204   y . As indicated by the arrow  210   v  ( FIG. 18 ), the lock bar  202  is slidably movable on the pin  204  in a vertical fashion within the confines of slot  200  from a lowered (lock) position as shown to a raised unlock position (not shown). The lock bar  202  is preferably held in the lowered (lock) position by gravity but can be spring-biased into the lowered position.  
      The inner wall V 1   b  of the right blade section D 3  defines a T-shaped slot  210  having an upper enlarged portion  210   e  and a reduced portion  210   r . The enlarged portion  210   e  is dimensioned and conformed so as to slidably accommodate the lock bar  202  when the blade section D 3  pivots from the unfolded to the folded position and when the lock bar  202  is in the raised position. The lock bar  202  defines first and second reduced-width neck portions  202   n   1 , 202   n   2  that are dimensioned for close receipt in the reduced portion  210   r  of the T-shaped slot  210 . As shown in  FIG. 17 , when the inner wall V 1   b  is located adjacent lateral wall V 2   b  of the central section D 2  (when section D 3  is unfolded), the first neck portion  202   n   1  of lock bar  202  is aligned with the reduced portion  210   r  of T-shaped slot  210  and, thus, the lock bar  202  is movable vertically downward into the first neck portion  202   n   1 . When the lock bar  202  is so positioned, the inner wall V 1   b  is captured owing to fact that the lock bar  202  cannot be slidably accommodated through the reduced portion  210   r  of the T-shaped slot  210 . As such, the right blade section D 3  is locked in the unfolded position.  
      To fold the right blade D 3  relative to the central blade D 2 , the lock bar  202  is raised vertically on pin  204  to its unlocked position so that it is moved into the enlarged portion  210   e  of T-shaped slot  210  of wall V 1   b  where it is slidably accommodated so as to allow pivoting movement of the right blade section D 3  via hinge HG 2 . Upon full folding movement of the blade section D 3 , the T-shaped slot  210  is moved into alignment with the second neck portion  202   n   2  of the lock bar  202  so that the lock bar can be lowered vertically with its second neck portion  202   n   2  received into the reduced-width portion  210   r  of the T-shaped slot  210 . In this case, the wall V 1   b  is unable to move in either direction (toward or away from wall V 2   b ) so as to lock the blade section D 3  in its folded position.  
      The inner end  202   a  of the lock bar protrudes from yoke structure  204   y  a distance sufficient to facilitate manual grasping of the inner end  202   a  by a user for purposes of lifting/lower the lock bar. The outer end  202   b  of the lock bar  202  defines an enlarged head  202   h  for the same purpose and, also, the head  202   h  is unable to pass through the T-shaped slot  210  in wall V 1   b  for any possible vertical position of the lock bar  202  so that the head  202   h  provides a stop for folding movement of the blade section D 3 .  
      With reference to  FIGS. 17 and 18 , it can be seen that the reduced-width section  210   r  of T-shaped slot  210  of wall V 1   b  is deeper than the thickness of the lock bar  202  so that the lock bar  202  lies beneath or inward from a shoulder  210   s  of the T-shaped slot  210  when in the locked position. This arrangement inhibits undesired vertical movement of the lock bar  202  out of the reduced-width section  210   r  of the T-shaped slot  210  during use of the pusher P′.  
      As noted, the fold-lock FL 1  is structured and operates in a corresponding fashion. As such, corresponding components shown in  FIG. 19  are identified with like reference characters, and further discussion of the structure and function of the fold-lock FL 1  is not required here for those of ordinary skill in the art. The independent operation of the fold-locks FL 1 ,FL 2  is deemed highly desirable in that operator&#39;s will sometimes desire to fold, and lock in the folded position, only one of the blade sections D 1 ,D 3  without the other.  
       FIG. 20  shows a folding pusher P″ that is identical to the pusher P′ except as otherwise shown and/or described. The pusher P″ does not include fold-locks FL 1 ,FL 2 . Instead, the pusher P″ comprises first and second open-locks OL 1 ,OL 2  and a single fold-lock FL″. The open-lock OL 1  is used to retain the left blade section D 1  in its unfolded (opened) position as shown; the open-lock OL 2  is used to retain the right blade section D 3  in its unfolded (opened) position as shown.  
      The open-lock OL 2  is shown in  FIG. 21  and comprises a base LB connected to the second lateral sidewall V 2   b  (or any other suitable portion) of central blade section D 2 . A pin LP is connected to the base LB and moves between extended and retracted positions. When extended, as shown, the pin LP captures the inner wall V 1   b  of right blade section D 3  adjacent the second lateral sidewall V 2   b  to prevent movement of the right blade D 3  from its unfolded position to its folded position. Of course, when the pin LP is retracted (moved upward in  FIG. 21 ) it is moved to a position where it no longer captures the inner wall V 1   b  so that folding movement of the right blade section D 3  is possible. Preferably, the pin LP is spring-biased to the extended position. The open-lock OL 1  is structured and operates in the same fashion as the open-lock OL 2  to engage and retain the inner wall V 1   a  of the left blade section D 1  in order to hold the left blade section D 1  in its unfolded position. In that case, the base LB is connected to the first lateral sidewall V 2   a  or other portion of the central blade section D 2 , and the pin LP selectively captures the inner wall V 1   a  of the left blade section D 1  to prevent folding movement of the blade section D 1 .  
      The sidewalls S 1 ,S 2  are locked to each other to maintain the pusher P″ in its folded position as desired for storage and/or transport as shown in  FIG. 22 . When the left and right blade sections D 1 ,D 3  of pusher P″ are folded relative to the central blade D 2  into opposed facing relation, the tips of sidewalls S 1 ,S 2  move adjacent each other, and the fold-lock FL″ is used to secure the sidewalls S 1 ,S 2  to each other. In the illustrated embodiment, the fold-lock FL″ comprises a tab T 1  that projects from first sidewall S 1  and that defines an aperture A 1 . The sidewall S 2  comprises at least one tab that has an aperture and, preferably, comprises first and second tabs T 2   a ,T 2   b  having respective aligned apertures A 2   a ,A 2   b . When the left and right blades D 1 ,D 3  are completely folded, the tab T 1  is received between the tabs T 2   a ,T 2   b  and the apertures A 1 ,A 2   a ,A 2   b  move into registration with each other. A lock pin KP is then inserted through the aligned apertures A 1 ,A 2   a ,A 2   b  to secure the sidewalls S 1 ,S 2  to each other in their folded positions. The pin KP preferably comprises a protruding spring-biased ball KB or the like that inhibits accidental dislodgement of the pin KP.  
      The pushers P,P′,P″, 100 P comprise sidewall gussets G 1 ,G 2  for strengthening the connection between the sidewalls S 1 ,S 2  and blade D or, in the case of the folding pushers P′,P″, between the sidewalls S 1 ,S 2  and the respective blade sections D 1 ,D 3 . Sidewall gussets G 1 ,G 2  can vary in size depending upon the size and type and expected application for the pusher.  
      The gusset G 2  is shown in  FIGS. 23-25  (the gussets G 1 ,G 2  are mirror images of each other and thus have a corresponding structure). It can be seen that the gusset G 2  comprises a chisel-shaped body GB, preferably defined as a one-piece construction from a steel plate folded at locations F 1 ,F 2  (other portions of the pusher are illustrated in broken lines to emphasize the structure of the gusset). As such, the gusset body GB comprises three main sections: a sloped face GF and first and second triangular sidewalls GS 1 ,GS 2  that taper moving outwardly away from the blade front DF. As best seen in  FIG. 25 , it is preferred that the sidewalls GS 1 ,GS 2  be arranged so that their outermost edges GS 1   e ,GS 2   e  lie parallel to each other or diverge away from each other as they extend forwardly away from the blade front surface DF.  
      It should also be noted that the folding pusher P′ preferably also comprises gussets G 3 ,G 4 ,G 5 ,G 6  ( FIG. 14 ) each defined from plate steel. The gussets G 3  and G 6  are used to strengthen the connections of the left and right blade sections D 1 ,D 3  to their inner walls V 1   a ,V 1   b , respectively; the gussets G 4  and G 5  are used to strengthen the connections between the central blade D 2  and its lateral sidewalls V 2   a ,V 2   b , respectively.  
       FIGS. 26-28  show a fixed-angle pusher  300 P that is substantially similar to the pusher P except as otherwise shown and/or described and, as such, the same reference characters are used except for new components. The fixed-angle pusher  300 P is designed to direct snow or other material being moved laterally as indicated by arrow L when the pusher is moved forwardly in a direction of operative movement as indicated by arrow F. As such, the blade D is angled relative to the direction of movement F, and the sidewall S 2 ′ differs from sidewall S 2  described above in that the sidewall S 2 ′ projects outwardly from front surface DF of blade not at all or only the minimal amount required for welding the sidewall S 2  to the blade D (sidewall S 1  is structured as described above). Substantially all of the sidewall S 2 ′ is located on the opposite side of the blade, i.e., projecting outwardly from rear face DR. Therefore, even if a minimal portion of the sidewall S 2 ′ projects outwardly from front face DF, the sidewall S 1  projects outwardly from front face DF much more than sidewall S 2 ′ to allow for snow or other material to overflow the blade D adjacent sidewall S 2 ′. A gusset G 2 ′ extends between the rear face DR of blade D and the sidewall S 2 ′ to reinforce the connection therebetween. As such, the sidewall S 1  projects outwardly from front face DF of blade more than sidewall S 2 ′, and sidewall S 2 ′ does not obstruct snow or other material flowing laterally L across front face DF of the blade away from the sidewall S 1 . The sidewalls S 1 ,S 2 ′ are arranged parallel to each other and, owing to the angled relationship of blade D relative to direction of movement F, the sidewall S 2 ′ trails the sidewall S 1  in the direction of movement F.  
      The pusher  300 P comprises a coupler structure C′ that is adapted to be engaged by an associated pusher-moving machine. In the illustrated embodiment, the coupler structure  300 C comprises a plurality of upper (first) ribs  302  and lower (second) ribs  304  that define therebetween a slot  300 L adapted for insertion of a bucket lip or other part of the associated pusher-moving machine to thus define a pick-up location. Chains are then used to secure the pusher  300 P to the machine, by engagement of the chains in the keyhole-shaped chain-engaging apertures N 1 ,N 2 ,N 3  defined in sidewalls S 1 ,S 2 ′.  
      The blade D is connected to coupler structure  300 C at an angle to encourage lateral movement of the snow or other material being pushed. In the illustrated embodiment, this is accomplished by use of at least one and preferably first and second parallel wedge-shaped coupler plates  306   a , 306   b  that are welded to an project outwardly from the second cross-support X 2 . The upper and lower coupler ribs  302 , 304  are connected respectively to the wedge-shaped coupler plates  306   a , 306   b  so that the distance from the slot  300 L (or other pick-up location) to the blade D is reduced closer to sidewall S 2 ′ and increased closer to sidewall S 1 . First braces  308  extend between and interconnect the upper coupler ribs  302  to the first cross-support X 1 , and second braces  310  extend between and interconnect the lower coupler ribs  304  to the third cross-support X 3 .  
      The present development has been described with reference to preferred embodiments. Modifications and alterations will occur to those of ordinary skill in the art to which the invention pertains, and it is intended that the claims be construed as encompassing all such modifications and alterations to the maximum possible extent according to the following claims as construed literally and/or according to the doctrine of equivalents.