Abstract:
This apparatus relates to shoring of deep excavations such as pits or trenches. It includes vertical rail posts arranged symmetrically in pairs that are spaced from each other along the excavation, articulated trusses and/or spreaders holding opposite rail posts against each other and large shoring panels sliding between adjacent rail posts on either side of the excavation. Each rail post has on either side one channel of a stepped or non-stepped cross section guiding vertically two or more shoring panels. In one variation, the inner and outer panel guides on one side of the vertical rail post reside in the same vertical plane. The connections between the rail post and the wall panels are partially or completely open. The open connections may be performed by magnetic forces arising from thin magnetic flat bars incorporated in the posts or the panels in the area of their contact. The articulated truss may be of a scissoring type and may be composed of triangular cells only and their members may have pinned connections. The cross members of the truss are pinned together in their mid-length enabling their relative rotation while their extremities are pinned into vertical members which have several rows of pinning holes in order to adjust the width of the trench without the need for additional spreaders. The vertical members of the truss slide formlockingly between a pair of opposite posts and could be adjusted at any level from the bottom of excavation. The truss may also include one or more rollers that facilitate its vertical mobility.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This is a continuation in part application of U.S. patent application Ser. No. 09/543,442, filed Apr. 5, 2000, which is incorporated in its entirety by reference. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to shoring apparatuses or devices for trenches, pits or other types of open excavations employed in the construction industry.  
         BACKGROUND OF THE INVENTION  
         [0003]    In the construction industry trenches, pits and other types of open excavations require the use shoring devices. Various known shoring devices include vertical rail posts, shoring panels and horizontal spreaders pressing the shoring walls against the side wall of the trench. Such shoring devices are called ‘Slide Rail Shoring Systems’.  
           [0004]    Previous slide rail shoring systems as disclosed in U.S. Pat. Nos. 3,910,053 and 4,657,442 (Krings) use a rail post having individual formlocking channel connections of ‘C’ type for sliding the panels. The load developed by the active pressure of the excavation walls is spread on very limited areas of contact between the post and panel. The stresses are highly concentrated at these areas becoming sources of high friction and temperature during the installation and removal of the system. Thus, damage is caused to both rail post and the panel, which strongly limits the application of such a system in pipeline productions, where the installation and removal of the system are effectuated continuously.  
           [0005]    U.S. Pat. Nos. 5,310,289 and 5,503,504 (Hess et al.), disclose a rail post having a unique channel for a maximum of two shoring walls, created by an outer panel and an inner panel. Only the outer panel slides formlockingly within the post; the inner panel is completely free and slides inside the outer panel and the rail posts. The design of the inner panel presents a risk of kicking in the trench when adjacent rail posts are not plumb. This is an important safety concern for the worker inside the trench. This phenomenon becomes prominent when the depth of excavation is over 20′ deep. On the other hand, shoring of excavations over 16′ deep requires the stacking and connection of two or more panels, which later must be removed at once. Removing two or more panels at once is a very difficult task and sometimes even impossible to accomplish even when heavy duty equipment is used. Yet another concern faced by this design is the difficulty of removing the inner panel when the deflection of the upper panel has begun. Also, it should be noted that a slide rail shoring system using differing types of panels requires a much bigger inventory of panels than a system that uses interchangeable panels.  
           [0006]    U.S. Pat. Nos. 3,950,952 (Krings), 5,310,289 and 5,503,504 (Hess et al) disclose very similar strut frames having a rectangular structure where the vertical members are equipped with rollers. These frames are designed to slide vertically between opposite rail posts in order to support the load coming from either side of the shoring walls. From an engineering standpoint, a frame having a rectangular cell is not a stable structure because it allows deformations without affecting the length of its members. For example, a rectangular cell may twist into a parallelogram. Additionally, the lower horizontal strut of the frame diminishes the pipe culvert thereby requiring special solutions for the installation of pipes having big diameters or of big box culverts.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    This invention relates to shoring devices for open excavations such as trenches and pits. The device includes vertical rail posts spaced apart from each other along the trench and arranged symmetrically on both sides of the trench. Opposite rail posts are kept vertically equidistant on either side of the trench by an articulated truss able to adjust the trench width. In one variation, the rail post has on both sides a channel of stepped cross section. Each step constitutes a vertical guide to slide at least one shoring panel. The shoring panels slide between each corresponding guide of adjacent rail posts and, according to the number of the guides, form two or more shoring walls. Thus, the panels slide past each other creating a stepped shoring wall from the top to the bottom of the excavation. The outermost and innermost steps of the shoring wall are called respectively “outer” and “inner walls” and so the panels. All other panels in between are called “intermediate”.  
           [0008]    In one shoring device, the connections between rail posts and shoring panels are maintained by magnetic forces arising from one or more magnetic flat bars incorporated in the lateral ends of the panels. For safety purposes partial locking may be used for the outer and inner panels. The intermediate panels slide completely free relative to the rail post.  
           [0009]    My articulated truss is of a scissoring type and may be composed of triangular cells. The cross members of the truss may be pinned at their midlength allowing rotation relative to each other. Such rotation allows adjustment of the truss width to several trench widths. The extremities of the cross members are pinned into vertical members of the truss which slide “formlockingly” along the rail post. For very deep applications, the vertical members of the truss generally have lateral guides for sliding additional panels at the bottom of the excavation.  
           [0010]    A shoring device of the type described above reduces the friction and the stresses in the contacts between components, while increasing the safety and ease of use in great depths. A rail post having channels of stepped cross section permits more than two shoring walls in that single channel structure without increasing the material expenditure. Interference between panels is also reduced. When the vertical guide of the rail post has a of stepped cross section, it eliminates the contact between rail post and back panel, while the contact area in the front panel is increased. Also, magnetic flat bars may be incorporated in the lateral ends of the panels thereby simplifying the connections between the rail post and panels, reducing the risk of damage.  
           [0011]    A slide rail system includes partially or completely open sliding connections for the panels along the rail post. Also, a rail post is described in which two or more panels may slide past each other, without need for stacking those panels. This tremendously extends the shoring depth for a slide rail shoring system.  
           [0012]    Another aspect of this invention is an articulated truss able to adjust to several trench widths, while providing for a big pipe culvert. The truss is thus able to perform a role in addition to supporting opposing rail posts. Also, accessory devices may be used in conjunction with the slide rail shoring system to increase safety and to facilitate its installation and removal.  
           [0013]    Another device for shoring a trench is a vertical rail that comprises opposing sides, each opposing side having an inner and outer wall panel guide. Each of the inner wall panel guides is adapted to slidably interlock with an inner wall panel and each of the outer wall panel guides is adapted to slidably interlock with an outer wall panel such that the inner and outer wall panels may be moved vertically.  
           [0014]    The vertical rail further comprises a vertically disposed truss guide that can cooperatively engage the movable truss. The truss guide may vary widely in form. In one variation, the truss guide is a tube having a round cross section. It may be mounted on the exterior or interior of the vertical rail. The truss guide may also be a vertical section of a tubular member having an arcuate cross section. The arcuate cross section may form an arc having an angle greater than 180 degrees.  
           [0015]    An inner wall panel and an outer wall panel may be provided wherein the inner wall panel and outer wall panel are equal in length. Also, the inner wall panel guide and the outer wall panel guide on one side of the vertical rail may be situated in the same plane, as opposed to having a stepped or other type of structure.  
           [0016]    The device may also include a mobile truss comprising a frame and end assemblies. Each end assembly is adapted to cooperatively engage the truss guide of the vertical rail when the vertical rails are positioned across from one another in the trench such that the truss may be vertically moved. The truss may include, in one variation, a round guide member that slidably accepts (or is accepted by) the truss guide of the vertical rail. Each end assembly of the truss may comprise at least one roller. Also, each end assembly of the truss may comprise an upper and lower assembly, each of which comprises at least one roller. The upper and lower assemblies may be connected to a horizontal strut via an upper beam and lower beam respectively.  
           [0017]    The truss and/or vertical rail may include one or more apertures such that the truss may be locked in place with a pin or fastener.  
           [0018]    A spreader for shoring applications comprises a frame and first and second end assemblies. Each end assembly comprises a vertical guide member having a circular cross section that is configured to slidably interlock with a vertical rail post such that the spreader may be moved vertically when the spreader is engaged with the vertical rail post.  
           [0019]    The guide member may be a circular tube that is either exteriorly or interiorly mounted to a spreader end assembly. It may be hollow or solid. Also, the guide member may be a vertical section of a circular tube having an arcuate cross section.  
           [0020]    Each spreader end assembly may include at least one roller. Also, each end assembly may comprise an upper roller assembly and a lower roller assembly. Each of the upper and lower roller assemblies may comprise at least one roller that contacts a surface of the vertical rail post when the spreader is slidably engaged with the vertical rail post. The guide member may extend vertically from the upper roller assembly to the lower roller assembly. Each end assembly may be configured to be pinnable to a vertical rail post.  
           [0021]    The frame of the spreader, in one variation of the invention, comprises at least one strut. It may comprise more than one or only one horizontal strut. Also, the frame and spreader may be nonarticulating.  
           [0022]    Another vertical rail for use in shoring trenches comprises opposing sides of stepped cross section. Each opposing side has an inner and outer wall panel guide. Each inner wall panel guide being adapted to slidably interlock with an inner wall panel and each outer wall panel guide being adapted to slidably interlock with an outer wall panel such that the inner and outer wall panels are substantially locked horizontally but may be moved vertically. The rail post further includes a truss guide being adapted to cooperatively engage an end assembly of a mobile truss such that the truss may be vertically moved.  
           [0023]    The stepped channel structure may comprise a central tube and at least two ancillary tubes mounted to the central tube. The ancillary tubes may be mounted up-front or on the sides of the central tube. The tubes may be rectilinear.  
           [0024]    Also, the stepped structure may be formed of a flange having at least two bends. One or more supporting plates may be mounted within the flange. One or more of the plates may be inclined. Instead of (or in addition to) the flange structure, the stepped channel structure may comprise a plurality of discrete straight plates, angular members, channel-shaped members, or a combination of one or more types of members. For example, the panel guides may be formed from a channel-shaped member having a U-shaped cross section.  
           [0025]    The shape of my truss guide may also vary. It may have, for example, a channel-shape (e.g., U-shape), angular, or round in cross section. It may be mounted on the exterior or interior of the vertical rail. In one variation, the truss guide is a vertical section of an elongated circular tube having an arcuate cross section. The truss guide may also be formed of a plurality of straight plates. One or more of the pieces or plates may be inclined.  
           [0026]    In another variation, the vertical rail post comprises at least one intermediate wall panel guide situated between the inner and outer wall panel guides. The intermediate guide is adapted to slidably engage an intermediate wall panel. This structure may comprise, for example, a flange having four bends, straight plates, angles, channel-shaped plates, or a combination of members.  
           [0027]    At least one of the truss guide and vertical rail may be adapted to receive a pin or other type of fastener to lock a movable truss in place.  
           [0028]    Other aspects and advantages of the invention will be appreciated upon review of the following description and drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 a  is a sectional view of a trench showing two rail posts and an articulated truss in between.  
         [0030]    [0030]FIG. 1 b  is a top view of a shoring system including shoring wall panels, vertical rail posts, and a movable truss.  
         [0031]    [0031]FIG. 1 c  is a top view of another shoring system including shoring wall panels, vertical rails, and mobile trusses.  
         [0032]    [0032]FIG. 2 is a sectional view taken along the line I-I of the FIG. 1A, showing a cross section of the rail post, shoring panels laterally on either side, and the top view of the vertical guide member of the articulated truss.  
         [0033]    [0033]FIG. 3 a  is a schematic, top, fragmentary, sectional view of a linear rail post depicting another connection with the articulated truss.  
         [0034]    [0034]FIG. 3 b  is a sectional view of a vertical rail having a stepped channel structure formed from rectilinear tubing.  
         [0035]    [0035]FIGS. 3 b ′ and  3   b ″ are a front view and side view respectively of a vertical rail post.  
         [0036]    [0036]FIG. 3 c  is a sectional view of another vertical rail having a stepped channel structure formed from rectilinear tubing.  
         [0037]    [0037]FIGS. 3D and 3E are partial sectional views of vertical rails having a stepped channel structure formed by flanges having two bends and an inclined support member.  
         [0038]    [0038]FIGS. 3F and 3G are sectional views of vertical rails having respectively U-shaped and circular-shaped truss guides for receiving and slidably engaging a movable truss.  
         [0039]    [0039]FIG. 3H is a sectional view of a vertical rail having a circular truss guide mounted on the exterior of the vertical rail.  
         [0040]    [0040]FIG. 3I is a sectional view of a vertical rail having a stepped channel structure formed from straight pieces.  
         [0041]    [0041]FIG. 3J is a sectional view of a vertical rail having a stepped channel structure comprising U-shaped channel members and straight plates.  
         [0042]    [0042]FIG. 4A is a schematic, top, fragmentary, sectional view of a linear rail post as shown in FIG. 1A, but with three guides for the panels on each opposing side.  
         [0043]    [0043]FIG. 4 b  is a sectional view of a vertical rail similar to that shown in FIG. 3C except the stepped structure shown in FIG. 4 b  can slidably receive an intermediate wall panel in addition to receiving inner and outer wall panels.  
         [0044]    [0044]FIG. 4 c  is a sectional view of a vertical rail similar to that shown in FIG. 3B except the stepped structure shown in FIG. 4 c  can slidably receive an intermediate wall panel in addition to receiving inner and outer wall panels.  
         [0045]    [0045]FIG. 4 d  is a sectional view of a vertical rail similar to that shown in FIG. 3D except that each flange shown in FIG. 4D includes four bends such that an intermediate wall panel may be slidably accepted.  
         [0046]    [0046]FIG. 5 shows a schematic, top, fragmentary, sectional view of a corner rail post, having guide channels oriented perpendicularly to each other for creating perpendicular shoring walls.  
         [0047]    [0047]FIG. 6 is a schematic, top, fragmentary, sectional view of a linear rail post as shown in FIG. 1A, but depicting guide channels that are completely open for sliding the panels.  
         [0048]    [0048]FIG. 7 shows a side view of the articulated truss similar to that shown in FIG. 1.  
         [0049]    [0049]FIG. 8 is a sectional view taken along the line  2 - 2  of FIG. 7, showing the pin connections between cross and vertical members of the truss.  
         [0050]    [0050]FIG. 9 shows a side view of the articulated truss having a horizontal strut connecting the upper part of the vertical members.  
         [0051]    [0051]FIG. 10 shows a side view of an articulated truss wherein the vertical members have, on either side, guide channels for sliding additional panels.  
         [0052]    [0052]FIG. 11 shows a three dimensional view of a shoring panel.  
         [0053]    [0053]FIG. 12 is a partial three-dimensional view showing the connection of the cutting edge at the bottom of the panel.  
         [0054]    [0054]FIG. 13 is a three-dimensional view of the lateral end of a panel incorporating magnetic flat bars.  
         [0055]    [0055]FIG. 14 shows a three-dimensional view of a sliding device fixed on the back of the rail post to slide formlockingly relative to another post.  
         [0056]    [0056]FIG. 15 shows a frame acting simultaneously on the upper and lower pairs of the rail posts.  
         [0057]    [0057]FIG. 16 is a three dimensional view of a hammering device to be affixed to the top of a panel for preventing damage to the panel during installation in the ground.  
         [0058]    [0058]FIG. 17 is a schematic, top, fragmentary, sectional view of a vertical rail having a round truss guide.  
         [0059]    [0059]FIG. 18 a  is a schematic, top, fragmentary, sectional view of a rail post having a round truss guide cooperatively engaged with a mobile spreader (or truss).  
         [0060]    [0060]FIG. 18 b  is a side view of the spreader shown in FIG. 18 a.    
         [0061]    [0061]FIG. 19 a  is a schematic, top, fragmentary, sectional view of a rail post having a round truss guide cooperatively engaged with a mobile spreader (or truss); the spreader includes a pair of rollers per axle.  
         [0062]    [0062]FIG. 19 b  is a side view of the mobile spreader shown in FIG. 19 a.    
         [0063]    [0063]FIG. 20 is a schematic, top, fragmentary, sectional view of another rail post having a round truss guide cooperatively engaged with a mobile spreader (or truss) similar to that shown in FIG. 17 except that the truss guide is mounted on the exterior of the rail post.  
         [0064]    [0064]FIG. 21 is a side view of the mobile spreader shown in FIG. 20. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0065]    Referring to the drawings where like numerals indicate like elements, various embodiments of the present invention are illustrated.  
         [0066]    A shoring device has two or more pairs of rail posts spaced apart from each other along the excavation. FIG. 1 a  illustrates a pair of linear rail posts  1 A and  1 B, located symmetrically on either side of the trench. Each rail post has laterally on either side at least two guides  2  and  3  for sliding large shoring panels between adjacent rail posts. The opposite rail posts  1 A and  1 B are kept vertically equidistant by an articulated truss  16 , which is composed of cross members  18 A and  18 B, pinned together at their midlength with the axle pin  19 , and by the vertical members  17 A and  17 B.  
         [0067]    A top view of an assembled shoring device is shown in FIGS. 1 b  and  1   c . FIG. 1 b  is a top view of an assembled shoring device including vertical rail posts  1 A,  1 B, corner posts, inner wall panels  6 A,  6 B outer wall panels  5 A,  5 B and a movable truss  16 . FIG. 1 c  is a top view of another shoring system including a plurality of vertical rails, wall panels, corner posts, and mobile trusses. The shoring system illustrated in FIG. 1 c  is preferred in large pit applications because it includes a plurality of adjacent vertical rails and mobile trusses.  
         [0068]    As shown in FIG. 2, the panel guides  2 A and  3 A are inside a unique channel of stepped cross section shaped by the pieces  8 ,  9 A,  10 A, and the angle  11 A. The round bars  14 A and  15 A partially lock the shoring panels  5 A and  6 A, and round bars  14 B and  15 B partially lock shoring panels  5 B and  6 B, thereby shaping the outer and inner shoring walls.  
         [0069]    The front side of the rail post  1 , as viewed looking into the excavation, has a ‘C’ channel shaped by the pieces  9 A,  9 B,  10 A,  10 B and  13 , wherein one vertical member of the articulated truss  16  slides and is horizontally locked by the T shaped piece  20 . The load originating from the excavation wall is transmitted from the panels to the articulated truss through the rail post and the rollers  21 A and  21 B which are supported by the axles  22 , axle holder  23 , and located at the extremities of the vertical member  17  of the truss.  
         [0070]    Additionally, as shown in FIG. 3 a , the channel for sliding connection between the articulated truss and the rail post could be exterior to the rail post and made by two angle pieces  26 A and  26 B.  
         [0071]    Stepped Channel Structure Formed from Rectilinear Tubing  
         [0072]    A cross sectional view of a variation of a linear rail post is shown in FIG. 3 b  comprising two rectangular tubes  11 A′,  11 B′ welded to a central rectangular tube  10 ′. In particular, one small tube is welded on each side of the central tube  10 ′.  
         [0073]    Although the central rectangular tube is shown in FIG. 3 b  as being larger than the side rectangular tubes, it need not be. The central tube may be smaller than the side or ancillary tubes. Also, the central and side tubing may have another cross sectional shape such as, e.g., square, rectangular, trapezoidal, etc.  
         [0074]    The use of tubing (e.g., rectilinear tubing) provides certain design advantages including but not limited to: 1.) savings in manufacturing cost as less straight plates and channels need to be welded, 2.) structural rigidity, and 3.) consistency in dimensions/tolerances as tubes of metal are readily available at various standard dimensions. Such stock tubing requires little (or no) additional processing.  
         [0075]    [0075]FIGS. 3 b ′ and  3   b ″ are front and side views respectively of a vertical rail post  1 . The vertical post includes a plurality of vertically spaced plates  13  each having an aperture for receiving (or interlocking) with a pin member to lock a movable truss (or spreader) in place. Once a desirable position is reached, a pin or another fastener (not shown) may be inserted into apertures in the truss and vertical rail post, locking the truss in place. The plates  13  may be welded to the vertical posts. Also, the apertures may be drilled into the vertical posts.  
         [0076]    [0076]FIG. 3C depicts another variation of a vertical rail post having a stepped channel structure formed by rectilinear tubing. In particular, FIG. 3C shows two square (or another cross-sectional shape) tubes  11 A′,  11 B′ welded up-front a central rectangular tube  10 ′. Inner and outer wall panel guides are shown as reference numbers  3 A,  3 B and  2 A,  2 B respectively.  
         [0077]    Stepped Channel Formed from Flange Having Two Bends  
         [0078]    [0078]FIG. 3D depicts a partial cross sectional view of another linear rail post  1  having a stepped channel structure. The opposing side shown in FIG. 3D includes two wall panel guides for slidably accepting an inner and outer wall panel. The inner and outer guides are formed by wall member (or ‘flange’)  11 B″ having two bends (B 1 , B 2 ). The linear rail also includes several support pieces  13 ,  13 B, and  13   c . In FIG. 3D, piece  13 B is shown inclined. These components may be welded together. Also, each component of the rail  1  may be symmetrical or nonsymmetrical about the center line (CL).  
         [0079]    [0079]FIG. 3E depicts another partial sectional view of a stepped channel structure similar to that shown in FIG. 3D except that pieces  13 A and  13 C are integrated as one member. Also, pin holes or apertures may be included in the support members of the rail such that the movable truss may be pinnable to the linear rail post  1 .  
         [0080]    The components of the vertical rail  1  (e.g., pieces  13 A,  13 B,  13 C) may thus be formed/welded in two different ways: 1.) they may be separately joined or 2.) they may be a single integrated member. Also, the features of the vertical rails shown in FIGS.  3 D- 3 E may be symmetrical or non-symmetrical about the center line (CL). Indeed, the opposing pieces  13 A,  13 B may mirror one another. Also, pieces  13 A,  13 B may be inclined or not inclined.  
         [0081]    [0081]FIG. 3F depicts a cross sectional view of another variation of a linear rail  1  having a combination of angle members  11 A,  11 B, and straight members  10 A,  10 B. Also, a channel member  13  is attached to the back surface of front plates  9 A,  9 B, providing a guide that slidably cooperates with the truss (not shown). This slidable cooperation between the rail and truss permits vertical movement while preventing horizontal movement.  
         [0082]    [0082]FIG. 3G depicts a cross sectional view of another linear rail similar to that shown in FIG. 3F but having a circular truss guide  13  for slidably receiving/engaging a vertical truss member. The circular guide  13  is situated between the front plates  9 A,  9 B and back plate  8 . A support member  13 C provides an attachment surface for the circular guide. The support member  13 C is mounted to flanges  11 A″,  11 B″ at the stepped region.  
         [0083]    Accordingly, a truss may be cooperatively engaged to the vertical rail post  1  via the circular guide  13 . Also, as will be discussed further herein, the truss (not shown) may include rollers, facilitating its vertical movement along the rail post.  
         [0084]    [0084]FIG. 3H depicts a cross sectional view of another linear rail  1  having flange members  11 A″,  11 B″. A round truss guide  26 ′ is shown mounted on the outside of the vertical rail. The truss guide  26 ′ is mounted up-front front plate  9 . The truss guide cooperates with a movable truss (not shown) to guide the truss vertically along the rail as described herein. The truss guide  26 ′ may be mounted to the vertical rail by welding. The truss guide  26 ′ may be a hollow tube, solid rod, or another type of member.  
         [0085]    Although the channel structure shown in FIGS. 3G, 3H comprises flange members, it may comprise different or additional pieces. For example, flat plates, tubular sections welded together, channel members, angle members, or any combination of these pieces may be joined to provide the channel structure for slidably accepting the shore wall panels or the truss guide member.  
         [0086]    [0086]FIG. 3I depicts a cross sectional view of another linear rail having a stepped channel structure. It is similar to that shown in FIG. 3F except that, unlike that shown in FIG. 3F, the linear rail post of FIG. 3I consists of straight pieces. In particular, the truss guide of FIG. 3I is formed by members  13 ,  13 A,  13 B. Members  13 A,  13 B are mounted on support plate  13 C. Also, inner wall channel plates  11 A″″,  11 B″″ are mounted to support plate  13 C. A pin hole is also provided in members  13 ,  13 C for locking the truss in place once it is in a desirable position. The pin holes may be vertically spaced along the vertical rail as shown, for example, in FIGS. 3 b ′,  3   b″.    
         [0087]    [0087]FIG. 3J depicts a cross sectional view of another variation of a linear rail having a stepped channel structure. The inner wall panel guides  3 A,  3 B for the inner wall panels, however, are formed, at least in part, by U-shaped channel members  11 ′″,  11 B′″. The outer wall guides  2 A,  2 B are formed by straight members  10 A,  10 B, back plate  8 , and the U-shaped channels referred to above. The vertical rail shown in FIG. 3J additionally includes a truss guide situated within the vertical rail post (as opposed to outside the vertical rail as shown in FIG. 3H).  
         [0088]    A magnetic bar  54 ′ may be mounted on the vertical rail post  1  to help secure the wall panels. In particular, a magnetic bar  54 ′ may be secured to a side of the front plate  9 B to urge an inner wall into proper alignment as it is slid (and locked) into position. Also, the magnetic bars may be placed elsewhere in vertical rail to encourage interlocking between the various components of the shoring system.  
         [0089]    Vertical Rail Posts Having Intermediate Panel Guides  
         [0090]    As shown in FIG. 4A, the rail post  1  could have laterally intermediate panel guides  4 A and  4 B shaped respectively by the angle pieces  12 A and  12 B. Therefore, an intermediate shoring wall may be formed by the shoring panels  7 A and  7 B.  
         [0091]    As shown in FIGS. 4 b  and  4   c  the rail post  1  may be comprised of tubular members to provide intermediate panel guides  4 A′ and  4 B′. In particular, the linear rail shown in FIG. 4 b  includes two small square tubing members  12 A′,  12 B′ welded up-front a central rectangular tubing member  10 ′. The rail post additionally includes straight pieces  2 A′,  2 B′, providing guides for receiving outer panel members.  
         [0092]    [0092]FIG. 4C shows a linear rail similar to that shown in FIG. 4B except that the smaller tubing members  12 A′,  12 B′ are mounted (e.g., welded) on the opposing sides of the central member  10 ′.  
         [0093]    In each of FIGS. 4 b - 4   c  apertures are present in support pieces  13 . The apertures are adapted to receive a portion of the movable truss (not shown) or a fastener that vertically locks the truss to the vertical rail.  
         [0094]    [0094]FIG. 4 d  depicts a cross sectional view of another linear rail having a stepped channel structure. The vertical rail shown in FIG. 4 d  is adapted to receive an inner, intermediate, and outer wall panel on each side. This vertical rail also comprises flange members  10 A″,  10 B″ each having four bends, providing intermediate guides for engaging intermediate panels. Also, a pin hole is provided through member  13 .  
         [0095]    The vertical rail depicted in FIG. 4 d  also includes a truss member guide  27  for vertically engaging a movable truss (not shown). The truss guide  27  is formed by straight plates  13 A,  13 B,  13 ,  9 A, and  9 B. Although straight plate  13 B is shown inclined, it need not be. Also, one or more of the other plates may be inclined or mounted at an angle. Also, a channel or angle member may be provided instead of individual straight plates to form the truss guide.  
         [0096]    Corner Posts for Supporting Shoring Wall Panels  
         [0097]    [0097]FIG. 5 shows a top fragmentary sectional view of a corner rail post for pit applications. Steps  11 A and  11 B are situated within perpendicular planes and allow panels  5 A and  5 B to slide and shape adjacent outer shoring walls. Likewise, the steps made by the pieces  9 A and  9 B hold the panels  6 A and  6 B of the inner shoring walls.  
         [0098]    In a corner rail post, round bar  15  (A or B) is optional because the inner panels  6 A and  6 B block each other due to the load coming from perpendicular directions and the fact that the inner panel is installed after the outer one.  
         [0099]    As shown in FIG. 6, channel guides  2 A,  3 A and  2 B,  3 B are used for guiding respectively panels  5 A,  6 A and  5 B,  6 B in the linear rail post, and may be completely open when using magnetic connections, or when not using magnetic connections. The panels may have the same length and mirror each other relative to piece  13 . Also, magnetic and non-magnetic components may be incorporated into the channels to provide the cooperating engagement or connection.  
         [0100]    As shown in FIG. 7, an articulated truss  16  may have only triangular cells. The cross members  18 A and  18 B are connected to the vertical members  17 A and  17 B via the extension  33 , flanges  34  and pin connector  30 . The pin connector  30  is fixed in one of holes  31  by pin  32 . For the same length of extensions  33 , the width of the truss could be easily modified by moving the pin connector from one hole  31  to another one. The articulated truss may be manipulated by lifting holes  36  of edges  35 .  
         [0101]    As shown in FIG. 8, a nut  37  secures pin  32  of the connector  30  to vertical member  17 B.  
         [0102]    [0102]FIG. 9 shows a horizontal strut  38  used in combination with articulated truss  16 . The strut  38  is connected to the vertical members of the truss via contact flanges  40  and pin  39 .  
         [0103]    Yet another type of articulated truss  16  is shown in FIG. 10, where vertical members  17 A and  17 B are extended way below the rollers  21 A and  21 B (collectively  21  in FIGS. 7 and 9) creating guides  4 A and  4 B for sliding additional panels in very deep excavations.  
         [0104]    Shoring Wall Panels  
         [0105]    As shown in FIG. 11, a shoring panel has guide members  41 ,  42  that slide inside the rail post guides, lifting plates  47  provided with a hole  48 , and a cutting edge  43  fixed at the bottom by a pin or bolt through hole  50 . To prevent damage to the panel, the upper part of it may be composed of two square tubes  46 A and  46 B slightly separated from each other and having a cover plate  45 . The bottom and the top of the panel may be identical and the panel may be used in either position.  
         [0106]    A thin flat plate  44  (a skin) may be affixed between lifting plates  47 ,  49  in the middle part of the panel only, to reinforce and reduce the bending of the panel due to the moment that increases parabolically from zero at its ends to a maximum at its middle. Additionally, the skin tends to protect the panel in the area where the bucket of the excavator is most active.  
         [0107]    The cutting edge  43  shown in FIG. 12, is pinned or bolted to the panel through holes  48 A and  48 B by the pins  50 A and  50 B via the plates  51 A and  51 B provided with holes respectively  52 A and  52 B.  
         [0108]    [0108]FIG. 13 illustrates another shoring panel  5  having a magnetic connection with linear and/or corner rail post by incorporating magnetic flat bars  54  on the sides of the panel guide  41 . To prevent damage to the magnetic flat bars, two plates  53  are fixed on the guide  41  to support the pressure of contact between post and panel.  
         [0109]    As shown in the FIG. 14, a sliding device  55  may be fixed to rail post  1  by bolts through holes  54 A and  54 B and into holes in the back side of the rail post. This is desirable when the depth of excavation is great and there is a need to slide a pair of rail posts together. The sliding device  55  has a formlocking T shaped piece  53  that goes inside the ‘C’ channel in front of the other rail post identical to the ‘T’ shaped piece  20  of the articulated frame shown in FIG. 2.  
         [0110]    As shown in FIG. 15, the truss supporting the twin pairs of rail posts acts simultaneously on the upper pair of rail posts,  1 A and  1 B, through the rollers  21 A,  21 B and on the lower pair of rail posts,  1 C and  1 D, via the rollers  21 C,  21 D. The truss could be an articulated type as indicated schematically by the dash-dot line or as a rectangular frame.  
         [0111]    [0111]FIG. 16 shows another accessory device to be fixed on the top of the panel  5  to prevent damages during the installation of the system. The accessory device is made by welding together the two plates  57  and  58 . The device can be pinned or bolted by the pin  60  passing through the hole  48  (passing through plate  49 ) and  59 .  
         [0112]    Vertical Rail Posts Having Round Truss Guide  
         [0113]    [0113]FIG. 17 depicts a partial cross sectional view of a shoring system  100  including a vertical rail  102 , inner wall panels  148 A,  148 B, outer wall panels  150 A,  150 B, and a mobile truss  130 .  
         [0114]    The vertical rail  100  includes a channel structure comprising opposing sides. Each opposing side includes inner wall panel guides  144 A,  144 B and outer wall panel guides  146 A,  146 B. The wall panel guides  144 A,B and  146 A,B slidably receive front wall panels  148 A,  148 B and back wall panels  150 A,  150 B respectively.  
         [0115]    The guides are formed by channel members  140 A,  140 B and straight members  142 A,  142 B. Rod members  138 A,  139 B and  139 A,  139 B are mounted in the guides and extend vertically. The rod members interlock with the wall panel guide members ( 149 A,  149 B,  151 A,  151 B), locking the wall panels in position. The components of the vertical rail  102  may be welded together. The channel members  140 A,  140 B may be tubing or formed by joining (e.g., welding) straight members together.  
         [0116]    Straight pieces  142 A,  142 B join the front plates  10 A,  10 B and back plate  136 . Additional reinforcing/redundant members or pieces may be welded to further secure the components together (not shown).  
         [0117]    As shown, the wall panel guides  144 A,  144 B and  146 A,  144 B slidably receive front wall panels  148 A,  148 B and back wall panels  150 A,  150 B respectively. Unlike the vertical rail posts described above, however, the channel structure shown in FIG. 17 is not stepped. The inner and outer wall panel guides  144 A,  146 A reside in the same plane. They also face the same direction. Consequently, the front and back wall panels may be the same length. This is an advantage since both the front and back wall panels may be made identical to one another, reducing the number of different types of components in the shoring system.  
         [0118]    The vertical rail post  102  shown in FIG. 17 also includes a round or circular truss guide  160  for slidably engaging a truss member  162  of the movable truss  130 . The truss guide  160  is shown behind front plates  110 A,  110 B. It is situated within the rail post  102 . The truss guide member  162  of the truss  130  cooperatively engages the truss guide  160 . The truss guide member  162  may be a rounded piece, tube, or rod attached to an end portion or extremity of the truss. The truss member  162  is slidably received by the truss guide  160 , preventing the rod from being moved horizontally while allowing it to be moved vertically along the rail post. Of course, there may be some degree of angular slop or wiggle room between the mobile truss and the vertical rail.  
         [0119]    The mobile truss  130  may include a frame and end assemblies. The frame may include one or more struts. It may be articulating or non-articulating. It may have a linear, rectangular, triangular, or other type of shape or cell shape. Each end assembly of the mobile truss preferably includes, as shown, one more rollers that contact the vertical rail post, facilitating vertical movement of the truss relative to the rail post.  
         [0120]    [0120]FIGS. 18A and 18B, depict an end assembly  200  of a spreader cooperatively engaged with a vertical rail post  102 . The vertical rail post is similar to that shown in FIG. 17. The end assembly of the spreader  200  includes a flange  202 , rectangular tube  204 , and vertical tube  206  that is connected to the rectangular tube  204  via member  208 . Back supports  210  are also shown that support axle  212 . A roller  214  rotates about axle  212 . The roller  214  contacts the front plate of the rail post and facilitates movement of the spreader vertically. Although only one roller is shown per axle in FIGS. 18A and 18B, more than one roller per axle may be incorporated into the end assembly  200 .  
         [0121]    A side view of the spreader  200  is shown in FIG. 18B including an upper and lower beam  220 ,  222  to support an upper and lower roller assembly respectively. The upper and lower roller assemblies are further supported by rectangular tube  204 . Additionally, flange  202  is shown mounted to strut  230 . The strut may be configured to span across an excavation site to support vertical linear rail posts positioned opposite one another. The frame of the spreader or truss  200  may include one or more struts. The struts may extend linearly across the trench, form rectangular cells, triangular cells, or other cell types.  
         [0122]    [0122]FIG. 19A illustrates another partial cross sectional view of a shoring system similar to that shown in FIG. 18A except the end assembly  200  of the spreader accommodates two rollers  215 A,  215 B per axle  212 . Also, as depicted in FIG. 19B, there is an upper set of rollers and a lower set of rollers.  
         [0123]    The spreader  200  also includes a truss guide member  206 . The truss guide member, as shown in FIG. 19A, may be slidably received by a truss guide  292  that is connected to the vertical rail post  300 . The truss guide  292  may be a round tube. In the shoring system depicted in FIGS.  19 A- 19 B, the truss guide  292  is disposed within the vertical rail. However, as discussed elsewhere in this application, the truss guide may be situated exterior to the vertical rail.  
         [0124]    [0124]FIG. 20 is a partial cross sectional view of another shoring system including an end assembly  200 ′ of a mobile truss or spreader. It is slidably connected to a vertical rail  302 .  
         [0125]    The vertical rail post  302  includes a circular truss guide  304  on the outside (or in front of) the front plate  306 . The truss guide  304  is adapted to be slidably received by a truss guide member  250  such that the spreader may be vertically moved along the vertical rail while horizontal movement is prevented.  
         [0126]    The vertical rail post shown in FIG. 20 also includes securing members  308 . The securing members  308  may be inclined and welded to the front and back plates of the vertical rail post. The securing members may also be welded or attached to other straight pieces, angles) tubes or flanges to further secure the vertical rail or to otherwise provide a supporting structure for the wall panels or truss guide.  
         [0127]    The vertical rail includes channel tubes  310 A,  310 B mounted on opposing sides of the rail post. In particular, the channel tubes  310 A,  310 B are mounted to each straight plate  312 A,  312 B respectively. The channel tubes and straight plates define inner wall guides  314 A,  314 B and outer wall guides  316 A,  316 B that receive front and rear shoring wall panels respectively. Additionally, a rod or vertical round member  318 ,  320  is mounted to the back plate  307  and the channel tubes  310 , as shown, to secure the wall panels. Each wall panel may be inserted into its corresponding wall panel guide and locked in place against the round member.  
         [0128]    [0128]FIGS. 20 and 21 also show an end assembly  200 ′ of a spreader for slidably engaging the vertical rail post. In particular, a truss guide member  250  of the spreader partially (or completely) coaxially surrounds truss guide  304  of the vertical rail. The truss guide member  250  may be, e.g., a vertical section of a tubular member. The cross section may form an arc having an angle greater than 180 degrees, and perhaps between 240 and 360 degrees.  
         [0129]    The end assembly of the spreader also includes a number of rollers  215 A,  215 B to facilitate vertical movement of the truss. In particular, the spreader includes two rollers  215 A,  215 B per axle  212 , similar to that shown in FIG. 19A. The end assembly  200 ′ of the spreader also includes an upper and lower set of rollers corresponding to an upper and lower beam  220 ,  222  as depicted in FIG. 21.  
         [0130]    An advantage of the shoring system depicted in FIGS. 20 and 21 is the use of wall panels having an equal length. The inner and outer wall panels may be identical to one another. Wall panels of equal length may be inserted or accepted by the shoring system shown in FIGS. 20 and 21 because the panel guides on each side of the rail post are in a common plane.  
         [0131]    All publications, patent applications, patents, and other references mentioned hereinbefore are incorporated by reference in their entirety.  
         [0132]    All of the features disclosed in the specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed, in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.  
         [0133]    The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.