Abstract: Multiple components of a floor mat system may each be formed of a resilient material such as foamed polyurethane. First and second channels are formed in the respective lower surfaces of first and second mat components, so as to inwardly extend from lateral boundaries thereof. The roofs of the channels are spaced above the general lower surfaces of the mat components. A first socket is formed to upwardly extend from the roof of the first channel, and a second socket is formed to upwardly extend from the roof of a second channel. A connector is used to join the mat components. Posts of the connector are received in the sockets, while a strap joining the posts is received within the first and second channels.

Abstract: A spacer (10) for creating a properly dimensioned gap during the installation of a flooring system, the spacer providing four non-adjustable portions to be selectively placed on a subfloor, each non-adjustable portion having a different width corresponding to an intended gap width.

Abstract: A retaining wall block including a pair of curved engagement surfaces extending convexly from a rear side of the block and being symmetrical about a transverse axis are configured to engage a planar surface of a setback lip of similar overlying blocks when stacked in successive courses to form a wall structure, where the curved engagement surfaces maintain a desired setback distance successive courses for straight, convex, and concave wall structures.

Abstract: A self-aligning interface for assembling a powertrain housing 210 of a wind turbine onto a support base 220 is provided. The support base 220 comprises a support surface 230 and the powertrain housing 210 comprises a housing surface 240. The support surface 230 and the housing surface 240 are configured to be in contact after assembly. The self-aligning interface comprises: one or more protrusions 250 on the support surface 230, wherein the one or more protrusions 250 comprises one or more walls 260 which are inclined with respect to the support surface 230; and one or more recesses 270 on the housing surface 240. In addition or alternatively, the self-aligning interface comprises one or more protrusions on the housing surface, wherein the one or more protrusions comprises one or more walls which are inclined with respect to the housing surface, and one or more recesses on the support surface.

Abstract: The system for constructing a retaining wall can be used to construct a segmental retaining wall for retaining earth, on either side, at two different levels. The system includes a plurality of blocks. Each block has laterally opposed first and second end portions, a central portion and a neck portion. The central portion is positioned between the first end portion and the neck portion, and the neck portion is positioned between the second end portion and the central portion. The central portion has a longitudinal length less than a longitudinal length of the first end portion, the second end portion has a longitudinal length less than the longitudinal length of the central portion, and the neck portion has a longitudinal length less than the longitudinal length of the second end portion. A plurality of pegs can vertically interlock adjacent blocks. Tie connectors can connect the blocks to an external pipe.

Abstract: The invention relates to a stone, in particular a dam stone for a flood dam. In order to be able to build a stable flood dam in an easy way, according to the invention a cover surface is provided with at least two ribs and an opposing base surface is provided with at least two grooves corresponding to the ribs so as to create an indirect connection between two stones by means of a third stone that can be detached by applying a tensile force perpendicular to the base surface. The invention further relates to the use of such a stone. In addition, the invention relates to a method for manufacturing a mass retention structure, in particular a flood dam.

Abstract: A multi-purpose interlocking masonry unit includes support members extending from its lower surface and port depressions formed in its upper surface. Each masonry unit can be placed on top of a previously placed masonry unit. The interlocking masonry unit allows for the rapid creation of a wall that is substantially straight and aligned while minimizing the need to perform precise measurements and make alignment adjustments during the creation process. Bonding material can be poured through the resultant wall ports, creating a matrix pattern of bonding material throughout the wall, which results in a stronger more durable construction.

Abstract: A building block (100) comprises a first mating portion and a second mating portion which are complementary. The first mating portion comprises a mating protrusion (140) which defines an axially extending through bore (144) and the second mating portion comprises an axially extending mating receptacle (180) which is complementary to the mating protrusion (140). The mating protrusion (140) and the mating receptacle (180) are in communication via the through bore (144), and a fastener anchoring device (146) adapted for engaging with an engagement means (920) of a fastener (900) is formed inside the through bore (144). The through bore (144) is adapted to permit axial insertion of the engagement means (920) of the fastener (900) into the mating protrusion (140).

Abstract: A pillar slab system using precast concrete pillar slabs for constructing a pillar, pergola or other stone structure comprises a body comprising at least four sides. Each exterior side surface comprises at least one simulated stone face. At least first and second side surfaces also have at least one simulated joint defining a visual separation between simulated stone faces. The simulated joints in the side surfaces are disposed at different horizontal positions, so that when one pillar slab is stacked on an identical pillar slab in a different orientation, the simulated joints in adjacent surfaces are vertically staggered relative to one another to avoid obvious repeating patterns and provide the appearance of a natural stone construction.

Abstract: This invention concerns a system of construction elements for the dry construction of a structure by way of shaped protrusions for mutual connection during assembly. It consists of construction element modules for raising walls, the ceiling and roof, and that the module consists of two elements with adjacent sides connected by a third element, creating a self-tightening connection, and the shaped protrusions of construction elements have two lateral contact surfaces, guiding (1) and self-tightening (2), inclined at specific angles ? and ?, and these angles are determined, respectively, between the perpendicular to the upper or lower protrusion surface and the guiding or self-tightening surface. The invention also includes applications of the specified system for raising compact and low structures, as well as for completing walls in buildings with skeletal constructions, and also as a block system for raising miniature constructions.

Abstract: A multi-purpose interlocking masonry unit includes support members extending from its lower surface and port depressions formed in its upper surface. Each masonry unit can be placed on top of a previously placed masonry unit. The interlocking masonry unit allows for the rapid creation of a wall that is substantially straight and aligned while minimizing the need to perform precise measurements and make alignment adjustments during the creation process. Bonding material can be poured through the resultant wall ports, creating a matrix pattern of bonding material throughout the wall, which results in a stronger more durable construction.

Abstract: A block for forming a structure, said block comprising a top, a bottom, a front wall, a back wall and two side walls, said block having disposed proximate the top at least one projection, said block having disposed proximate the bottom thereof at least one recess, wherein when the structure is formed from a plurality of said blocks, said at least one projection of one block engages with said at least one recess of another block.

Abstract: The present invention relates to a block deck used as the interior or exterior material of a building. More specifically, disclosed is a block deck using concrete, wherein a hollow portion is formed inside and filled with concrete so as to exhibit superior strength. The present invention provides a block deck including: a frame member formed with a hollow portion inside; and filler formed of a concrete material so as to be filled in the hollow portion. At this time, the concrete may be foamed according to desired strength with a foaming rate in the range of 0-50%. The frame member may be formed of natural wood, synthetic wood and synthetic resin materials. And, the frame member may be formed integrally or divisionally into two or more so as to be coupled, wherein coupling is carried out by being fitted in a sliding manner.

Abstract: A wall block having at least one weight bearing pad on an upper or lower surface of the block and a compression head and methods of making the block and making walls with the block.

Abstract: A concrete casted paving stone of rectangular shape is described and has two pairs of opposed parallel side walls. In a first of the two pairs of side walls, an engaging projection is formed in one side wall and a through slot in the other side wall for receiving the stone-engaging projection of another paving stone therein. The second pair of opposed parallel side walls each have a slot and a further stone-engaging projection in a section thereof. The stone-engaging projections of the second pair of side walls are disposed adjacent the side wall of the first pair which contains the slot and the slot extends through the rear wall of these stone-engaging projections. The paving stone may be used as a permeable paving stone wherein to evacuate water from an upper surface of a paved surface into the underlying support bed.

Abstract: In an exemplary embodiment of this invention, corrugated board is folded into a building system. The building system comprises a plurality of blocks and connectors. The blocks are rectangular cuboid in shape. The bottom and top sides of the blocks have rectangular arrays of holes. The blocks may be releasably connected by aligning the top holes of one block with the bottom holes of another block, and then inserting connectors into the aligned pairs of holes, one connector per aligned paid of holes. The ends of the connectors that are inserted are circular or equiangular polygonal in shape. In some embodiments, compression is used to releasably hold the connectors in place.

Abstract: An artificial flagstone for use in combination with other similar flagstones for covering a surface with a natural random look, the flagstone having a generally hexagonal body comprising a first, second, third, fourth, fifth and sixth consecutive vertices; a first pair of first and second sides extending radially from the first vertex; a second pair of third and fourth sides extending radially from the third vertex; a third pair of fifth and sixth sides extending radially from the fifth vertex; wherein the sides of at least one of the first, second and third pair of sides have at least one split deviation along their length and are respectively rotational images of each other, and the artificial flagstone has no rotational symmetry when rotated about a central axis.

Abstract: A precast concrete solid core paver block which has a first pair of flat parallel side walls and a second pair of transverse parallel side walls. One side has at least one block engaging projection in one or more portions thereof and spaced between a top and bottom surface of the paver block. The opposed side wall has a slot to receive in close sliding fit the at least one block engaging projection of an adjacent one of the paver blocks for side-by-side interengagement while permitting horizontal displacement of the adjacent paver block and the block engaging projection thereof while preventing vertical displacement thereof wherein a top face of the paver blocks lie in a substantially common planar surface. Spacers form open joints about each block in portions thereof to communicate with a support bed and form a permeable paved surface.

Abstract: A building element is in the form of hollow brick having a plane major face and dovetailed projections on an opposite major face for slotting together with similar building elements for the construction of masonry structures. The building element has internal through cavities for housing of operative connections of distribution systems and the like, arranged according to an array parallel to said plane major face, which is formed with references for identification from outside of each through cavity.

Abstract: The present invention relates to a paving stone having stone flanks which are oriented perpendicular to the laying plane, and wherein the paving stone has interlocking elements of a stone flank of an adjacent paving stone.

Abstract: A structural element for use as a brick, construction block, panel, floor or suchlike in the building trade, comprises at least one part made of conglomerate material, such as concrete and suchlike, to which an insert made of insulating or filling material is constrained, to define peripherally at least a connection face for connection to another structural element, the connection face has visible a first surface of the insert and at least a connected second surface of the part made of conglomerate material. On the connection face one or more other structural elements are able to be combined, along a support plane (R, R1, R2) provided in correspondence with the connection face, so as to be laid and stably connected by means of a layer of binder material. The second surface has a seating made longitudinally and lowered with respect to the support plane (R, R1, R2), on which seating the layer of binder material is located. The seating has a determinate depth (D), with respect to the support plane (R, R1, R2).

Abstract: A modular wall block is adapted for being assembled together with a number of other blocks in stacked courses to form a retaining wall. The wall block has a front and rear, top and bottom, and opposing sides. The top and bottom define respective substantially planar stacking surfaces. A shear lug projects from one of the planar stacking surfaces of the top and bottom. A block-locating jut is formed with at least one of the opposing sides, and projects from the side at a point intermediate the top and bottom towards one of the planar stacking surfaces. The block-locating jut defines a base surface substantially coplaner with the stacking surface, and a lug-engaging shoulder adapted for engaging a shear lug of a wall block located in an adjacent stacked course.

Abstract: A method for forming a structural paver deck assembly includes fastening structural decking panels across a bare frame structure. One or more of the decking panels includes an upper panel surface having a non-planar contoured decking panel surface. A paver decking surface is seated over the plurality of structural decking panels to form a paver decking surface. Seating includes positioning a plurality of paver pieces on the structural decking panels including interfittingly engaging the paver pieces to the non-planar contoured decking panel surface. Seating further includes aligning the plurality of paver pieces in at least one specified direction, wherein the paver pieces includes paver contour surfaces along a lower surface having a corresponding shape to the non-planar contoured decking panel surface. Interfitting engagement of the paver contour surfaces with the non-planar contoured panel surface orients the one or more paver pieces in the at least one specified direction.

Abstract: A plastic construction block for storage of water, food, medicine, staples, construction materials, or any other item that needs to be contained for storage and shipping. The construction block can also be used in the construction of a bunker, wall, or the like structure through conventional building construction by filling of the block with sand or dirt. The construction block is substantially rectangular in shape having an enlarged fill port on one end with a resealable cap. The interior of the block is hollow and sized to hold about 3.4 fluid gallons. Apertures extend through the block and are used for receipt of anchoring posts. Each aperture further having a raised protrusion formed integral along one surface and a receptacle placed around each aperture on the rear surface. The raised protrusion interlocking with a receptacle on a rear surface of an adjoining construction block for aligning similar shaped construction blocks.

Abstract: There is disclosed a method of connecting a geogrid to a segmental retaining wall with the use of positive connectors between upper and lower blocks.

Abstract: A method and mould for forming upwardly extending protrusions on a wall masonry block during moulding of the block. The method including pouring a flowable concrete mixture into a lower mould to form a body of said wall masonry block, applying a head shoe to form an upper section of said wall masonry block, the head shoe including a first mould portion for forming an upper bedding face of said block and a second mould portion for forming at least one protrusion extending upwardly from the upper bedding face, the head shoe being shaped to improve the flow of said concrete mixture into the second mould portion during compression of the block, and removing the masonry block from the mould.

Abstract: A modular wall block is adapted for being assembled together with a number of other blocks in stacked courses to form a retaining wall. The wall block has a front and rear, top and bottom, and opposing sides. The top and bottom define respective substantially planar stacking surfaces. A shear lug projects from one of the planar stacking surfaces of the top and bottom. A block-locating jut is formed with at least one of the opposing sides, and projects from the side at a point intermediate the top and bottom towards one of the planar stacking surfaces. The block-locating jut defines a base surface substantially coplaner with the stacking surface, and a lug-engaging shoulder adapted for engaging a shear lug of a wall block located in an adjacent stacked course.

Abstract: A retaining wall block has spaced-apart front and rear sections interconnected by two laterally spaced-apart side sections that jointly define a through-cavity that extends through the block from a top face thereof to a bottom face thereof. Two or more protuberances protrude outwardly from the top face of the front section frontwardly of the through-cavity. A groove extends laterally in the bottom face of the front section frontwardly of the through-cavity. The groove is located and dimensioned relative to the protuberances so that two blocks can be stacked one atop another in staggered relation with one or more protuberances of the lower block engaged with one but not both of a front wall and a rear wall of the groove of the upper block and the upper block setback with respect to the lower block.

Abstract: A set of concrete pavers is formed by a plurality of pavers being arranged in a paver row, and a plurality of paver rows being arranged to form a row. A number of parallel, adjacent rows form linear or meandering joints in the end-paver region of the rows when the rows are laid together. At least one section of the upper delimiting surface of the pavers is convexly cambered towards the outside, and projections on the side faces of the pavers form support elements for the adjacent pavers. The support elements, in combination with projections on adjacent pavers, create spaces that act as water-drainage openings in the joint regions. The pavers in each set include not only paving blocks with a length-to-height ratio of less than or equal to 4 but also at least one paving slab with a length-to-height ratio greater than 4.

Abstract: Concrete wall blocks are described with features facilitating use of the wall blocks to construct each of: a wall section with set back; and, a vertical wall without set back. Wall blocks, kits or sets of wall blocks, and wall sections with various sized blocks are described. Further methods of assembly and use are described. Also, features selectively usable in various types of wall blocks are described.

Abstract: A block has a front face with a first surface of non-planar roughness including at least 10% and not more than 90% of the area of the front face. The front face includes a second surface that is even and generally planar, with at least 10% and not more than 90% of the area of the front face. In one example, the first surface is a split face, and the second surface is a burnished split face. In another example, the first surface is a molded face, and the second surface is burnished. Methods of making a block include molding, curing, in some implementations splitting, and then burnishing. Walls can be constructed from these blocks.

Abstract: A polygonal paving stone has a plurality of substantially planar sides extending perpendicularly between parallel upper and lower faces of the stone. A row of substantially identical and outwardly projecting narrow coupling members of a predetermined member width on each of the sides are separated by spaces of a predetermined space width. These narrow members are positioned on the respective sides such that when a plurality of the paving stones are fitted together with their upper faces generally coplanar the narrow coupling members of confronting sides of adjacent paving stones fit between one another A single wide coupling member on each of the sides has a width a greater than that of the member width of the narrow members and smaller than the space width so it can fit between two of the narrow members of a confronting side of an adjacent paving stone.

Abstract: A set of paving stones is provided, including a plurality of different paving stones that each respectively have a polygonal base surface, side surfaces with ribs and a visible side, for paving surfaces with optionally different laying patterns.

Abstract: A retaining wall block for an engineered block retaining wall system having an integrally formed head, neck and body, in which one generally planar front face of the body forms a visible part of the wall, the body having two pin holes, two clean out holes, each of which terminates within the body of the block, and two pin receiving openings, the pin receiving openings being configured to receive a free end of a lock pin provided in a pin hole of a block placed there under so as to interlock the blocks with a predetermined setback. The pin holes and pin receiving openings being positioned such that a plane extending perpendicular to the generally planar front face passes through one, and only one, of said pin holes or said pin receiving openings.

Abstract: An irregular, tessellated building unit comprises x primary elements, wherein x is an integer equal to or greater than 1. The primary element is a rotational tessellation having a plural pairs of sides extending in a generally radial direction from plural vertices, respectively. In each pair, the two sides are rotationally spaced by an angle that is divided evenly into 360 degrees. Preferably, all of the sides are irregularly shaped, but one or more sides could be wholly or partially straight. Optionally, spacers are provided on the sides of each unit. A wide variety of units may be constructed having different numbers and arrangements of primary elements. As all the units are combinations of primary elements, they readily mate with each other. A surface covering comprises a multiplicity of units assembled to form a continuous surface without overlap between units and without substantial gaps between units. A structure, such as a wall or column can be formed of building units of the invention.

Abstract: The present invention relates to a support structure including a plurality of mats, each mat including a substantially fixed matrix of spaced tubular rings. The mats are vertically stacked such that the tubular rings are co-extensive and form a matrix of tubular columns. Materials may be poured into the columns and into the void region between the columns, and geotextile or geomembrane-type fabric may wrap the mats and materials to form a block. The blocks may be arranged in one or more horizontal layers, and may be stacked and staggered with respect to blocks in a lower layer. A method of installing the structure is also disclosed.

Abstract: A set comprising a construction element and a masonry tool, said construction element comprising a first face and a second face substantially oriented in planes parallel to the axes of the length l and width d and separated from each other by a height h, said first face comprising at least two ribs oriented substantially parallel to the axis of the length l and separated in each case from each other in the axis of the width d by a first so hollow, and a third face and a fourth face, substantially oriented in planes parallel to the axes of the width d and height h, and separated by a length l, said first hollow is open at least on said third face, said masonry tool comprises at least two sections sized so as to be able to be placed straddling in each case on one of the ribs and each arranged so as to be is able to slide on said rib on which it is placed.

Abstract: A dry-stackable masonry brick having a top surface, a bottom surface, a front surface, a rear surface, and opposing side surfaces. The brick is provided with a plurality of channels, which extend along the top, bottom and one side of the brick. The channels are configured and arranged so that they are able to receive a projection from one or more adjacent bricks in an interlocking relation. The brick may be positioned on either of the opposing sides in a vertical orientation, with the bottom side up, or even with the rear surface facing forwardly. The front and rear surfaces of the brick may be provided with different surface treatments to increase the number of differently configured walls that may be constructed. Moreover, the front and rear surfaces may be provided with marginal areas that are configured so that they are able to receive and retain filler material.

Abstract: A retaining wall is formed of a series of courses of blocks, each of which includes a core. Engagement members are interposed between the blocks in adjacent courses for preventing relative forward movement between the blocks in adjacent courses. Each engagement member is mountable to the rear web of a lower block, and includes an upstanding projecting portion that engages the rear web of an upper block for preventing forward movement of the upper blocks relative to the lower blocks. The upstanding projecting portion engages the rear web of the upper block so that the front face of the upper block is located rearwardly of the front web of the lower block, to expose an upwardly open forward portion of the core of the lower block. The exposed portion of the lower block core may receive planting media, to enable plants to be planted in the exposed core of the lower block.

Abstract: A structural element for the construction of any type of buildings, comprising a first “C”-shaped element with equidistant cavities at least on one of its faces and a second element in the shape of a continuous strip with equidistant angular folds, whereby once both structural elements are assembled to each other, the angular folds of the metallic strip are projected through the cavities of the “C”-shaped structural element.

Abstract: A construction apparatus including a body having a front, a rear, a top, a bottom, and first and second opposite sides. The front has a front surface having a plurality of block images configured to generally depict a plurality of courses of blocks, each of the courses having a respective course width. The first and second sides have generally complementary step shapes including at least two rises and at least one run between the rises, each rise being about equal to one of the course widths or a sum of a plurality of the course widths.

Abstract: A retaining wall block engagement system comprises a plurality of wall blocks connected with connectors. Each wall block comprises a top surface and opposing bottom surface, a front surface and opposing rear surface and first and second opposing side surfaces. Each side surface includes a shoulder portion and a pair of recesses extending upwardly from bottom surface. The recesses separated by a web portion. A plurality of generally H-shaped or h-shaped connectors are configured to interlock a block in a given course with a block in an adjacent course of blocks.

Abstract: An irregular, tessellated building unit comprises x primary elements, wherein x is an integer equal to or greater than 1. The primary element is a rotational tessellation having a plural pairs of sides extending in a generally radial direction from plural vertices, respectively. In each pair, the two sides are rotationally spaced by an angle that is divided evenly into 360 degrees. Preferably, all of the sides are irregularly shaped, but one or more sides could be wholly or partially straight. Optionally, spacers are provided on the sides of each unit. A wide variety of units may be constructed having different numbers and arrangements of primary elements. As all the units are combinations of primary elements, they readily mate with each other. A surface covering comprises a multiplicity of units assembled to form a continuous surface without overlap between units and without substantial gaps between units. A structure, such as a wall or column can be formed of building units of the invention.

Abstract: A retaining wall block having a front surface, a rear surface, side surfaces, a top surface, and a bottom surface. Each side surface comprises a first section, a second section, a third section, and a fourth section, with the sections configured and arranged to allow a plurality of blocks to be arranged in a convex wall structure. The retaining wall block may be combined with one or more pins, which may engage vertically adjacent blocks and which may engage an end of an earth anchor. The retaining wall block may be cast in a mold box whose depth and width are configured and arranged to substantially approximate the depth and width of a standard sized pallet.

Abstract: An invertible retaining wall block comprises a front portion, a rear portion and a neck portion connecting the front portion and rear portion. A projection extends outwardly from the block to interlock with similar blocks in adjacent courses of blocks. One or more notches are provided to the front portion in order to allow the base course of blocks to be placed in an inverted orientation with respect to subsequent courses because the notch provides clearance for the protrusion.

Abstract: A block for use in constructing a multiple course retaining wall comprises a top surface, a bottom surface spaced apart from the top surface, opposing side surfaces, a front surface and a back surface. The bottom surface may include a pair of contacting portions that contact a top surface of a lower course of blocks when the block is placed on a lower course of blocks and a gap defining portion located between the contacting portions. The front surface may have generally planar upper and lower edges when viewed in front elevation and has a width extending between the side surfaces that is greater than the width extending between the side surfaces of back surface. At least one of the contacting portions may intersect front surface.

Abstract: The invention relates to an artificial stone floor element with a basic shape that corresponds to the combination of a plurality of square basic elements, especially to an angular floor element. The floor element includes projections and recesses along its peripheral sides of the basic element when seen from the centre of the respective top face of the basic element is substantially point-symmetric with respect to its mid-point. The floor element in further embodiments includes a profile that consists of three projections and three recesses.

Abstract: A block for use in constructing a retaining wall and comprising a body having a central cavity extending vertically there through and defining front, rear, and side walls. The side walls diverge rearwardly from the front of the block to the rear. Stabilizing wings extending outwardly at the rear of the side walls. Positioning wedges extend from the bottom surface and include flat forward surfaces for positioning the block with respect to the blocks in a lower tier of blocks. The flat forward surfaces of the positioning wedges are located nearer the front surface of the block than is the inner surface of the front wall, thereby enabling a retaining wall created from the blocks to have each successive higher tier offset from the adjacent lower tier by a set distance. The block of the present invention provides a stable block having a large coverage area at a low weight.

Abstract: A block for use in constructing a multiple course retaining wall. The block has a substantially planar top surface, a front surface, wherein said front surface is of a substantially curvilinear shape, a rear surface, opposed side surfaces, and a bottom surface. The bottom surface has a predetermined area and a non-planar portion, with the non-planar portion comprising a continuous area making up at least one-quarter of the bottom surface and creating a cavity between the bottom surface of the block and a top surface of a lower course of blocks when the block is placed on the top surface of the lower course of blocks. The cavity allows dirt and other foreign matter to exist between successive courses of blocks without creating instability between the block and the lower course of blocks.

Abstract: A segmental retaining wall system comprising a plurality of wall blocks. Each wall block comprises an interior face for forming an interior surface of a segmental retaining wall, an exterior face for forming an exterior surface of the segmental retaining wall, first and second sides that extend from said exterior face to said interior face, a top surface, and a bottom surface. In addition, a plurality of wall blocks include apparatus for retaining a reinforcement member to the segmental retaining wall. In one arrangement, this apparatus comprises a channel that is defined by a front wall, a rear wall, and a channel bottom surface. This channel is provided in one of the faces and surfaces, and includes an inwardly extending shoulder.