CA2090387C

CA2090387C - Block components for a mortarless retaining wall

Info

Publication number: CA2090387C
Application number: CA 2090387
Authority: CA
Inventors: Bertin Castonguay; Gilles Desharnais; Elie Chiniara; Jean Boucher; Rejean Castonguay; Eric Milot; Waguih Chikani
Original assignee: Groupe Permacon Inc
Current assignee: Oldcastle Building Products Canada Inc
Priority date: 1993-02-25
Filing date: 1993-02-25
Publication date: 1996-08-13
Anticipated expiration: 2013-02-25
Also published as: CA2090387A1

Abstract

The present invention relates to a block for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in rows. The block has a groove able to receive a rear, downwardly extending, flange of another block for interlocking and setting the other block forward a predetermined distance with respect to an underlying block.

Description

2~903~7 ~ The present invention relates to setback type blocks for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in rows or courses. The present invention in particular relates to blocks having block bodies comprising relatively planar top and bottom surfaces.
The present invention also relates to slabs which are cast on their sides and which can be broken into a number of blocks having different shapes and which may be used for the construction of retaining walls using the (known) rear setback technique.

It is known to use a capping or crown block having a relatively flat or planar top surface for the final layer of blocks of a retaining wall. It is in particular known to make a retaining wall from molded (concrete) blocks wherein the blocks are weighted and shaped so as to be stackable in setback fashion so as to angle the wall to counter the pressure of landfill behind the wall. It is, for example, known to provide blocks having opposed planar support surfaces with a block interlock member(s) for interlocking and setting back successive courses of blocks; the interlock member may for example comprise a flange disposed along the rear and bottom of a retaining wall block; see, for example, U.S. patents nos. 2,313,363 and 5,017,049 Although it is also known to provide flat topped\bottomed retaining wall blocks for the body of a wall, 2~303~7 such blocks are shaped or configured such that a flat topped\bottomed capping or crown block may be used as the last uppermost block layer only in a set back relation with respect to the underlying block.

Known types of blocks for retaining walls commonly present a squarish or rectangular aspect such that when used to prepare convexly curved retaining walls the product wall is pockmarked or interrupted by cavities between adjacent blocks. In order to convexly curve the outer wall surface, adjacent rectangular blocks must be disposed such that the side surfaces adjacent the front surface are spaced apart although they may abut at their rear corner edges, i.e. the joint between adjacent blocks is open. Such cavities are not always desired by the owner of the wall; the owner may prefer a more or less uniform uninterrupted wall surface.

It is also known to cast a series of blocks on their sides so as to facilitate the clean definition of interlocking elements for a setback type block for a retaining wall; see U.S. patent no. 5017,049 mentioned above.

At present the user of retaining wall blocks must predetermine the number and types of blocks needed to make a retaining wall of given length and height (e.g. of a given number of block layers). Since the calculations with respect to the number of 2~03~7 blocks may be relatively complicated for a do-it-yourself type of person, it is not uncommon for such person to either underestimate or overestimate the number of blocks needed for a retaining wall of given number of block courses; in the first case the person is inconvenienced by having to obtain additional blocks and in the second case by having leftover blocks for which the person may have no use.

Accordingly, it would be advantageous to have a block construction or configuration which would facilitate the preparation of retaining walls having convex as well as concave curved exposed (i.e. outer) surfaces which present a relatively uninterrupted continuous surface, i.e. the joint between adjacent blocks is closed so that an exposed wall surface is not pockmarked with cavities and presents a relatively aesthetically pleasing surface.

It would also be advantageous to have blocks for use in the construction of a mortarless retaining wall wherein the blocks useful as capping blocks may optionally be used in the body of the wall as well as for the top covering block layer, i.e.
multi-purpose capping blocks.

It would be advantageous to have block configurations or forms which would allow a capping block to be offset forwardly or rearwardly as desired by a wall builder.

2091~8~

It would further be advantageous to have a wall making system or kit which would exploit a few interchangeable block forms.

It would also be advantageous to have a kit of blocks which may be structured such that within a given set of parameters the user is able to exploit all of the blocks to make a retaining wall.

It would be advantageous to have block configurations which would facilitate the production or casting of a plurality of blocks as a set of blocks which, within predetermined set of parameters, may all be used without any block being leftover.

STATEMENT OF INVENTION

The present invention generally relates to a grooved block for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in rows. The grooved block is provided with an intermediate groove able to engage (e.g.
angularly receive) a block interlock member of another block for interlocking and offsetting forwardly, if desired, the other block a predetermined distance with respect to the underlying block.

Thus, in accordance with an aspect, the present invention thus provides a grooved block, for use in the construction of a ~903~7 mortarless retaining wall wherein a plurality of blocks are stacked in successive offset courses, the grooved block comprising a block body, and a block interlock member, the block body having relatively planar top and bottom support surfaces, the top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, the block interlock member extending from the planar bottom surface adjacent the rear surface, the block interlock member and the block body being configured such that when the grooved block is disposed on an underlying retaining wall block having a the block body, the interlock member is able to engage the rear surface of the underlying block for offsetting the grooved block rearwardly a predetermined distance with respect to the underlying block, the grooved block being characterized in that the block body has a groove interrupting the planar top surface adjacent the rear surface, and the groove is sized such that when an overlying retaining wall block, having a the block body and a the block interlock member, is disposed on the grooved block, the groove is able to engage the interlock member of the overlying block for offsetting the overlying block forwardly a predetermined distance with respect to the grooved block.

In accordance with the present invention the groove may consist of a (single) groove which may, for example, extend from one respective side surface of the block body to the other respective side surface thereof;
and the interlock member may consist of a (single) flange disposed at the rear and bottom of a block, the flange, for example, extending from one side surface to the other; the interlock member may of course, if desired, comprise a flange member comprising a plurality of spaced flange elements rather than a single continuous flange body.

In accordance with a particular aspect of the present invention, the groove may, for facilitating the formation of a curved wall (segment), be sized so as to be able to receive a flange transversely with respect to the longitudinal axis of the groove, i.e. the width of a groove may be larger than the thickness of the flanges such that the flange may be angularly disposed in the groove (as shall be discussed below).

2~387 The grooved block may, desirably, have a generally tapered configuration wherein the front and rear surfaces thereof are generally parallel to each other, the front surface being larger than the rear surface, ie. to facilitate the construction of a convex curved wall (segment).

In accordance with a particular aspect of the present invention, the grooved block may, for example, have a generally trapezoidal configuration wherein the front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with the front and rear surfaces thereof, the other side surface defining a generally acute angle with the front surface thereof.

A block may if desired be a right hand block or a left hand block.

In accordance with the present invention, the expressions "right hand block" and "left hand block" are to be understood herein as characterizing the configuration of one block as being the mirror image of the configuration of another block such that one block cannot be superimposed on the other notwithstanding their similarity in shape. In accordance with the present invention a trapezoidally configured block may, for example, be a right hand block or a left hand block. The expression "right hand block" as applied to a trapezoidally configured block is thus to be understood as characterizing the block as having a configuration or shape such that when viewed in perspective from the front toward the front and top surfaces thereof, the acute angle is on the right side of the block;
similarly, the expression "left hand block" as applied to a trapezoidally configured block is thus to be understood as characterizing the block as having a configuration or shape such that when viewed in perspective from the front toward the front and top surfaces thereof, the acute angle is on the left side of the block.

The rear surface of the grooved block may be uninterrupted from top to bottom surface. However, if desired, the grooved block may include a rear notch connecting the top and rear surfaces, i.e. a portion of the rear surface adjacent to the top surface may be offset toward the front of the block. The notch may be separated from the groove in the top surface by a projection;
the top of the projection defining the portion of the top surface adjacent to the rear surface. The notch may extend from one side surface to the other side surface of the grooved block. The offset rear surface of the notch may be used for engagement with the interlock member of an overlying block so as to offset the overlying block rearwardly with respect the underlying block.

A grooved block of the present invention may be advantageously 20~0387 used in the body of a retaining wall so as to optionally provide for offsetting of an overlying (crown) block forwardly or rearwardly as desired by the wall builder. The grooved block may in particular be used for the supporting course of blocks on which a capping or crown course of blocks may rest in either rearward or forward offset position relative to the supporting course of blocks; the capping block(s) having generally uninterrupted planar top surface(s) e.g. generally flat top surfaces.
Thus in accordance with another aspect the present invention provides, in a method for the construction of a mortarless retaining wall wherein a plurality of blocks are laid down one over the other so as to define a plurality of successive offset courses of blocks, the wall including an upper crown course of blocks resting on an underlying lower course of blocks, the upper crown course and the underlying lower course of blocks each comprising a plurality of retaining wall blocks, each the retaining wall block comprising a block body, and a block interlock member, the block body having relatively planar top and bottom support surfaces, the top and bottom surfaces being generally parallel to each other, 203~387 a front surface, a rear surface, and two side surfaces, the block interlock member extending from the planar bottom surface adjacent the rear surface, the block interlock member and the block body of a retaining wall block being configured such that when the retaining wall block is disposed on an underlying block having a the block body, the interlock member of the retaining wall block is able to engage the rear surface of the underlying block for offsetting the retaining wall block rearwardly a predetermined distance with respect to the underlying block, the improvement wherein the blocks of the underlying lower course of blocks are configured relative to the blocks of the crown course so that blocks of the crown course may be offset forwardly or rearwardly relative to blocks of the lower course of blocks, wherein the lower course of blocks comprises a plurality of grooved retaining wall blocks, wherein the block body of each grooved retaining wall block has a groove interrupting the planar top surface adjacent the rear surface, (- the groove, for example, consisting of a groove which extends from one side surface of the block body to the other side surface thereof), and wherein the groove of a grooved retaining wall block is sized 2030~87 such that when an overlying block, of the crown course of blocks, is disposed on the grooved retaining wall block, the groove thereof is able to engage the interlock member of the overlying block for setting the overlying block forward a predetermined distance with respect to the grooved retaining wall block. The grooved block may take on the forms such as described herein.

In order to facilitate the construction of a retaining wall (segment) the present invention also relates to wall kits.

Thus, the present invention in accordance with another aspect provides a kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, the wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and the wall including an upper crown course of blocks resting on an underlying lower course of blocks, the kit being characterized in that the kit comprises a plurality of grooved blocks and a plurality of other blocks 5 each of the blocks comprising a block body, 2~03~7 and a block interlock member, the block body having relatively planar top and bottom support surfaces, the top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, the block interlock member extending from the bottom surface adjacent the rear surface, the block interlock member and the block body of a the block being configured such that when a the block is disposed on an underlying the block, the interlock member thereof is able to engage the rear surface of the underlying block for offsetting the block rearwardly a predetermined distance with respect to the underlying block, each of the grooved blocks having a groove for receiving a the block interlock member, a the groove of a grooved block interrupting the top surface adjacent the rear surface thereof, (e.g. the groove may for example consist of a groove extending from one side surface to the other side surface thereof), and being sized such that a block interlock member of a the other block is engageable therein for interlocking therewith, and the grooved and other blocks each being configured such that when a grooved block underlies an overlying other block, the block interlock member of the overlying other block is engageable in the groove of the underlying grooved block and the front surface of the overlying other block is able to be offset forwardly relative to the front surface of the underlying grooved block, the number of the grooved and other blocks in the kit being such that the crown course of blocks is able to consist of the other blocks and the immediately underlying lS lower course of blocks is able to consist of the grooved blocks.

The grooved blocks of the kit may take on the various forms or formats such as for example described herein. The other block may, for example, take on a rectangular configuration or alternatively, take on the same configuration as the grooved blocks except for the groove; these latter blocks may be used in the body of a retaining wall or as a crown block for the crown course of blocks since the top surface thereof is relatively planar.

2~387 A kit in accordance the present invention may, for example, comprise a plurality of first right hand (grooved) blocks a plurality of second left hand (grooved) blocks a plurality of third right hand other blocks and a plurality of fourth left hand other blocks each of the blocks comprising the herein described block body and block interlock member and the first, second, third and fourth blocks each having the herein mentioned generally trapezoidal configuration. The configuration of the first block may for example in particular be a mirror image of the configuration of the second block; similarly, the configuration of the third block may be a mirror image of the configuration of the fourth block.

If it is desired that a wall have a curved longitudinally extending aspect it is advantageous that the groove of the grooved blocks be sized (i.e. the width) so as to allow the interlock member, such as a (straight) flange, to be received or engaged therein more or less parallel to the longitudinal length of the groove and optionally also transversely to the longitudinal axis of the groove. An angular engagement will allow an overlying block to overlap the junction between two adjacent underlying blocks such that the flange may be disposed in a portion of both of the underlying blocks.

A kit in accordance with the present invention may, for example, comprise a plurality of slabs which are splittable into the blocks described herein. The slabs may be splittable into any suitable pairs of blocks, i.e. a slab may comprise any suitable combination of two blocks as described herein.

In accordance with a particular aspect of the present invention, a kit may be characterized in that it comprises a plurality of first slabs a plurality of second slabs and a plurality of third slabs each of the slabs having cleavage groove means for allowing breakage of each slab into two separate blocks, the front face of each separate block being exposable on breakage of the corresponding slab into two separate blocks, each of the first slabs is breakable along the cleavage groove means thereof into a the first block and a the second block, each of the second slabs is breakable along the cleavage groove means thereof into a the a first block and a the fourth block, each of the third slabs is breakable along the cleavage groove means thereof into a the a second block and a the third block, and each of the slabs is configured such that prior to breakage thereof into the respective separate blocks, the side surface 20~0387 of one respective block which defines a right angle with the front surface thereof and the side surface of the other respective block which defines a right angle with the front surface thereof are generally disposed in the same plane.

As previously mentioned, each of the above mentioned slabs has cleavage groove means for allowing breakage of each slab into two separate blocks. The cleavage means may take any (known) form. The cleavage means may for example comprise opposed splitting grooves in the top and bottom surface of a slab;
similar opposed cleavage grooves may also if desired be disposed on opposed side surfaces such that the splitting grooves ring the slab. The various slabs referred to herein may be split in any (known) manner which provides the desired front surface; i.e. by machines or other methods known in the art.

As mentioned one type of retaining wall block which may be used in conjunction with the grooved block of the present invention is a wall block having a rectangular configuration; this type of wall block may be used in generally straight sections of wall either as a crown or wall body element; a straight wall (section) may also include tapered blocks as herein described.
A curved (segment of a) wall associated with straight wall (segment) is preferably constructed only of tapered blocks as described herein the grooves being sufficiently wide so as to allow angular engagement of the interlock member as herein described. 2 0 9 ~ 3 8~

Thus, in accordance with another particular aspect the present invention provides a kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks (for example three such courses), the wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and the wall including an upper crown course of blocks resting on an underlying lower course of blocks, the kit being characterized in that the kit comprises a plurality of grooved blocks a plurality of other blocks and a plurality of rectangular blocks each of the blocks comprising a block body, and a block interlock member, the block body having relatively planar top and bottom support surfaces, the top and bottom surfaces being generally parallel to each other, a front surface, 209û3~7 a rear surface, and two side surfaces, the block interlock member extending from the planar bottom surface adjacent the rear surface, the block interlock member and the block body of a the block being configured such that when the block is disposed on an underlying the block, the interlock member thereof is able to engage the rear surface of the underlying block for offsetting the block rearwardly a predetermined distance with respect to the underlying block, each of the grooved and other blocks having a generally trapezoidal configuration wherein the front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with the respective front and rear surfaces thereof, and the other side surface defines a generally acute angle with the respective front surface thereof, each of the rectangular blocks having a generally rectangular configuration wherein the front and rear surfaces thereof are generally parallel to each other, the two side surfaces thereof are generally parallel to each other, and each of the side surfaces define a generally right angle with the front and rear surfaces thereof, 209~3B7 each of the grooved blocks having a groove for receiving a the block interlock member, a the groove of a grooved block ~
interrupting the planar top surface adjacent the rear surface thereof, (the groove may, for example, consist of a groove extending from one side surface to the other side surface thereof), and being sized such that a block interlock member of a the other block or rectangular block may be engaged therein for interlocking therewith, and the grooved, other and rectangular blocks being configured such that when a grooved block underlies an overlying other or rectangular block, the block interlock member of the overlying other or rectangular block is engageable in the groove of the underlying grooved block and the front surface of the overlying other or rectangular block is able to be offset forwardly relative to the front surface of an underlying grooved block, the number of the grooved, other and rectangular blocks in the kit being such that the immediately underlying lower course of blocks is able to consist of the grooved blocks and the crown course of blocks is able to consist of blocks selected from the other blocks and the rectangular blocks provided that the crown course of blocks of the 2090~87 curved portion of the wall is able to consist of the other blocks, and the number of the grooved and other blocks in the kit being such that all of the courses of blocks below the crown course of blocks of the curved portion of the wall are able to consist of blocks selected from the grooved and other blocks.

If desired the number of the grooved, other and rectangular blocks in the kit may be such that the crown course of blocks for a straight wall or straight portion thereof is able to consist of rectangular blocks and the crown course of blocks of a curved portion of the wall is able to consist of the other blocks.

A kit of the present invention may, in particular, be configured for use in the construction of a retaining wall comprising 3 courses of bricks or more, e.g. 6, 9, and higher.
In accordance with the present invention the above mentioned tapered grooved, tapered other and rectangular blocks may be present in a kit in a proportion of 4:2:3 respectively; the proportion of various blocks gives the user of the kit the flexibility of making a straight flat capped (crowned) wall or a wall having a flat capped straight portion and a flat capped curved portion. The curved part of a wall may for example make up about 50% of the longitudinal length of the wall in the case wherein the kit is configured to make a wall of three courses and has at least 18 rectangular blocks.

As previously indicated a block may take on a right or left hand configuration. Thus in accordance with another particular aspect, the present invention provides a kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, the wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and the wall including an upper crown course of blocks resting on an underlying lower course of blocks, the kit being characterized in that the kit comprises a plurality of first right hand blocks a plurality of second left hand blocks a plurality of third right hand blocks a plurality of fourth left hand blocks and a plurality of fifth blocks, each of the blocks comprising a block body, and a block interlock member, 209038~
the block body having relatively planar top and bottom support surfaces, the top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, the block interlock member extending from the planar bottom surface adjacent the rear surface, the block interlock member and the block body of a the block being configured such that when the block is disposed on an underlying the block, the interlock member thereof is able to engage the rear surface of the underlying block for offsetting the block rearwardly a predetermined distance with respect to the underlying block, each of the first, second, third and fourth blocks having a generally trapezoidal configuration wherein the front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with the front and rear surfaces thereof and the other side surface defines a generally acute angle with the front surface thereof, the configuration of the first block being a mirror image of the configuration of the second block, 2090~87 the configuration of the third block being a mirror image of the configuration of the fourth block, each of the fifth blocks having a generally rectangular S configuration wherein the front and rear surfaces thereof are generally parallel to each other, the two side surfaces thereof are generally parallel to each other, and each of the side surfaces define a generally right angle with the front and rear surfaces thereof, each of the first and second blocks having a groove for receiving a the block interlock member, a the groove of a first or second block interrupting the planar top surface of a respective block adjacent the rear surface thereof, (for example, the groove may consist of a groove extending from one respective side surface to the other respective side surface thereof), and being sized such that a the block interlock member of the third, fourth or fifth blocks is engageable therein for interlocking therewith, and the first, second, third and fourth blocks being configured such that when a first or second block underlies an overlying third, fourth or fifth block, the block interlock member of the 209D~8~

overlying third, fourth or fifth block is engageable in a the groove of the underlying first or second block and the front surface of the overlying third, fourth or fifth block is able to be offset forwardly relative to the front surface of an underlying first or second block the number of the first, second, third, fourth and fifth blocks in the kit being such that the underlying lower course of blocks is able to consist of blocks selected from the first and second blocks and the crown course of blocks is able to consist of blocks selected from the third, fourth and fifth blocks provided that the crown course of blocks of a curved portion of a wall is able to consist of blocks selected from the third or fourth blocks, 15 and the number of the first, second, third and fourth blocks in the kit being such that all of the courses of blocks below the crown course of blocks of a curved portion of the wall are able to consist of blocks selected from the first, second, third and fourth blocks.

If desired, the number of the first, second, third, fourth and fifth blocks in a kit may be such that the crown course of blocks for a straight wall or straight portion thereof is able to consist of the fifth blocks and the crown course of blocks for a curved portion of a wall is able to consist of blocks 20so387 selected from the third and fourth blocks.

As mentioned above a kit of the present invention may, in particular, be configured to have various proportions of various blocks so as to give the user of the kit the flexibility of making a straight capped wall or a wall having a flat capped straight portion and a flat capped curved portion.
For example, if the retaining wall is to have 3 courses of bricks, the above mentioned first, second, third fourth and fifth blocks, may be present in a kit in a proportion of 2:2:1:1:3 respectively such that the curved part of a wall may for example make up about 50% of the longitudinal length of the wall in the case wherein the kit has at least 18 rectangular blocks. On the other hand if the above mentioned first, second, third fourth and fifth blocks, are present in a kit in a proportion of 5:5:2:2:4 respectively the curved part of a wall may for example make up about 2/3 of the longitudinal length of the wall in the case wherein the kit has at least 12 rectangular blocks.
In accordance with an additional particular aspect of the present invention, a kit may be characterized in that it may comprise a plurality of first slabs a plurality of fourth slabs a plurality of fifth slabs 2~03~7 a plurality of sixth slabs and a plurality of seventh slabs, each of the slabs having cleavage groove means for allowing breakage of each slab into two separate blocks, each of the first slabs is breakable along the cleavage groove means thereof into a the first block and a the second block, each of the fourth slabs is breakable along the cleavage groove means thereof into a the a first block and a the fifth block, each of the fifth slabs is breakable along the cleavage groove means thereof into a the a second block and a the fifth block, each of the sixth slabs is breakable along the cleavage groove means thereof into a the a third block and a the fifth block each of the seventh slabs is breakable along the cleavage groove means thereof into a the a fourth block and a the fifth block, (preferably, for example, each of the slabs is configured such that prior to breakage thereof into the respective separate blocks, a side surface of one respective block defining a right angle with the front surface thereof and a side surface of the other respective block defining a right angle with the front surface thereof are generally disposed in the same plane) and 209~387 the front face of each separate block is exposable on breakage of the corresponding slab into two separate blocks.

In accordance with another particular aspect the present invention provides, a kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, the wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and the wall including an upper crown course of blocks resting on an underlying lower course of blocks, the kit being characterized in that the kit comprises one or more slabs D
a plurality of slabs E
a plurality of slabs F
and a plurality of slabs G, the slabs D, E, F, and G being present in the kit in a proportion of 1:4:3:2 respectively, slab D having first and second cleavage groove means for allowing breakage of slab D into a separate block K, a separate block Km and a separate block L, a front face of each separate block K and Km being exposable on breakage of the slab along the first cleavage groove means to separate the block K
therefrom, a rear face of the block Km and a front face of the 20~0387 block L being exposable on breakage of the slab along the second cleavage groove means to separate the block L therefrom, slab E having first and second cleavage groove means for allowing breakage of slab E into a separate block K, a separate block L and a separate block M, the slab E including a third cleavage groove means disposed between the first and second cleavage groove means for allowing breakage of slab E into a separate block N and a separate block O, a front face of each of the blocks K and M being exposable on breakage of the slab along the first cleavage groove means to separate the K block therefrom, a rear face of the block M and a front face of the block L being exposable on breakage of the slab along the second cleavage groove means to separate the block L therefrom, a front face of each separate block N and 0 being exposable on breakage of the slab, along the third cleavage groove means, into the separate blocks N and O, slab F having first and second cleavage groove means for allowing breakage of slab E into a separate block L, a separate block M and a separate block P, the slab F including a third cleavage groove means disposed between the first and second cleavage groove means thereof for allowing breakage of slab F
into two separate blocks O and Q, a front face of each separate block P and M being exposable on breakage of the slab along the first cleavage groove means to separate the block P therefrom, 2~9~387 a rear face of the block M and a front face of the block L
being exposable on breakage of the slab along the second cleavage groove means to separate the block L therefrom, a front face of each separate block O and Q being exposable on S breakage of the slab, along the third cleavage groove means, into the separate blocks O and Q, slab G having cleavage groove means for allowing breakage of slab G into a separate block R and a separate block S, the block R having another cleavage groove means disposed adjacent a rear end thereof for allowing breakage thereof into a separate block T and a block fragment, the block S having another cleavage groove means disposed adjacent a rear end thereof for allowing breakage thereof into a separate block U
and a block fragment, a front face of each separate block R and S being exposable on breakage of the slab, along the cleavage groove means, into the separate blocks R and S, a rear face of each respective block T and U being exposable on breakage of a respective block T and U along a respective other cleavage groove means to separate a respective block fragment therefrom, each of the separate blocks comprising a block body, and a block interlock member, the block body having relatively planar top and bottom support surfaces, the top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, the block interlock member extending from the planar bottom surface adjacent the rear surface, the block interlock member and the block body of a the block being configured such that when the block is disposed on an underlying the block, the interlock member thereof is able to engage an abutment surface of the underlying block for offsetting the block rearwardly a predetermined distance with respect to the underlying block, each of the blocks K, Km~ M and N having a generally rectangular configuration wherein the front and rear surfaces thereof are generally parallel to each other, the two side surfaces thereof are generally parallel to each other, and each of the side surfaces define a generally right angle with the front and rear surfaces thereof, each block M comprising a respective third cleavage groove means, each block N comprising a respective first cleavage groove means, each of the blocks R, S, T and U having a generally trapezoidal configuration wherein the front and rear surfaces thereof are - 2~80387 generally parallel to each other, one side surface defines a generally right angle with the front and rear surfaces thereof and the other side surface defines a generally acute angle with the front surface thereof, the block O comprising a respective second cleavage groove means, the block Q comprising a respective first cleavage groove means, the blocks O and Q each having a configuration wherein the front and rear surfaces thereof are generally parallel to each other, one side surface defines a generally right angle with the front and rear surfaces thereof and the other side surface comprises a first surface portion and a second surface portion, the first surface portion extending from a respective cleavage groove means to the front surface such that the first surface portion and the cleavage groove means define a generally acute angle, the second surface portion extending from a respective cleavage groove means to the rear surface generally parallel to the other side surface, the configuration of block R being a mirror image of the configuration of block S, the configuration of block T being a mirror image of the configuration of block U, each of the blocks L, T and U having an offsetting groove for receiving a said block interlock member, a said offsetting groove of a block L, T and U
interrupting the planar top surface of a respective block adjacent the rear surface thereof, and being sized such that a said block interlock member of a block K, Km and P is engageable therein for interlocking therewith, and the blocks L, T, U, K, Km and P being configured such that when a block L, T, or U underlies an overlying block K, Km or P, the block interlock member of the overlying block K, Km or P is engageable in a said offsetting groove of the underlying block L, T or U and the front surface of the overlying block K, Km or P is able to be offset forwardly relative to the front surface of an underlying block L, T or U.

As in the case of the previously described kits, the number of blocks L, T, U, K, Km and P in the above kit is such that the underlying lower course of blocks is able to consist of blocks selected from the blocks L, T and U and the crown course of blocks is able to consist of blocks selected from the blocks K, Km and P provided that the crown course of blocks of a curved portion of a wall is able to consist of blocks selected from the blocks P; additionally, the number of the blocks L, T and U

2090~8~

in the kit is such that all of the courses of blocks below the crown course of blocks of a curved portion of the wall are able to consist of blocks selected from the blocks L, T and U.

S In accordance with the present invention, the acute angle of a block may take any suitable or desired value and is chosen on the basis of the desired minimum radius of curvature that a course of blocks is intended to impart to a convexly curved outer wall surface without pockmarks or cavities. The acute angle may, for example, range from 60 to 85 degrees (e.g. 75-76 degrees). The acute angle and the length of the front face will dictate the minimum radius of curvature of a convexly curved wall segment; a convex wall segment will have a minimum radius of curvature since the side surfaces of adjacent blocks will abut at this radius.

It is to be understood herein, that if a "range" is mentioned with respect to a particular characteristic of the present invention, the present invention relates to and explicitly incorporates herein each and every specific member and combination of sub-ranges or sub-groups therein whatsoever.
Thus, any specified range or group is to be understood as a shorthand way of referring to each and every member of a range or group individually as well as each and every possible sub-ranges or sub-groups encompassed therein. For example, with respect the acute angle, the mention of the range of 60 to 85 degrees is to be understood as specifically incorporating herein each and every individual angle as well as sub-range of angles, such as for example 61 degrees, 75 degrees, 65 to 75 degrees, 80 degrees, 60 to 80 degrees, etc..; similarly with respect to ranges for length, weight etc...

In drawings which illustrate example embodiments of the present invention:
Figure 1 is a top view of an embodiment of a (first) slab comprising first and second block elements;
Figure 2 is a side view of the slab of figure 1 showing the cleavage groove means;
Figure 3 is a perspective view of the separate blocks obtainable by splitting of the slab of figure l;
Figure 4 is a top view of an embodiment of a (fourth) slab comprising first and fifth block elements;
Figure 5 is a side view of the slab of figure 4 showing the cleavage groove means;
Figure 6 is a perspective view of the separate blocks, obtainable by splitting of the slab of figure 4, figure 6 being on the same page of drawings as Figure 3;
Figure 7 is a top view of an embodiment of a (fifth) slab comprising second and fifth block elements;
Figure 8 is a side view of the slab of figure 7 showing the cleavage groove means;

igure 9 is a perspective view of the separate blocks obtainable by splitting of the slab of figure 7, figure 9 being on the same page of drawings as figure 3;

35 a :

Figure 10 is a top view of an embodiment of a (seventh) slab comprising fifth and fourth block elements;
Figure 11 is a side view of the slab of figure 10 showing the cleavage groove means;
Figure 12 is a top view of an embodiment of a (sixth) slab comprising third and fifth block elements;
Figure 13 is a side view of the slab of figure 12 showing the cleavage groove means;
Figure 14 is a top view of an embodiment of a (second) slab 10comprising first and fourth block elements;
Figure 15 is a side view of the slab of figure 14 showing the cleavage groove means;
Figure 16 is a top view of an embodiment of a (third) slab comprising second and third block elements;
15Figure 17 is a side view of the slab of figure 16 showing the cleavage groove means;
Figure 18 is a top view of an embodiment of a (eighth) slab comprising third and fourth block elements;
Figure 19 is a side view of the slab of figure 18 showing the 20cleavage groove means;
Figure 20 is a top view of an embodiment of a (ninth) slab comprising two fifth block elements;
Figure 21 is a side view of the slab of figure 20 showing the cleavage groove means;
25Figure 22 is a schematic side view of stacked first, second and fifth (or third or fourth) blocks elements, the fifth 2~90387 block element being used as a crown element which is set back;
Figure 23 is a schematic side view of stacked first, second and fifth (or third or fourth) blocks elements, the fifth element being used as a crown element which is set forward;
Figure 24 is a schematic side view of stacked first, second and fifth (or third or fourth) blocks elements, the fifth element being used as a wall body element which is set back;
Figure 25 is a top view of stacked courses of first, second and fourth block elements;
Figure 26 is a top view of stacked first and second block elements with the main body of the first block elements being cut away to expose the disposition of the flanges thereof in the grooves of the underlying second block elements;
Figure 27 is a schematic view of a curved retaining wall constructed with known rectangularly configured retainer wall blocks;
Figure 28 is a schematic view of a curved retaining wall constructed with tapered blocks of the present invention;
Figure 29 is a top plan view of a filled mold for side casting of slabs in accordance with the present invention.
Figure 30 is a diagrammatic representation of the front of a 20~3~7 wall with three courses of blocks, each block being identified as to type, the wall being straight;
Figure 31 is a diagrammatic representation of the front of a wall with three courses of blocks, each block being identified as to type, the wall having a straight and a curved segment ;
Figure 32 is a diagrammatic representation of the front of a wall with three courses of blocks, each block being identified as to type;
Figure 33 is a diagrammatic representation of the front of a wall with three course of blocks, each block being identified as to type; and Figure 34 is a partially cutaway perspective view of a retaining wall in accordance with the present invention.
Figure 35 is a top view of an embodiment of a slab D;
Figure 36 is a side view of the slab of figure 35 showing the cleavage groove means;
Figure 37 is a top view of an embodiment of a slab E;
Figure 38 is a side view of the slab of figure 37 showing the cleavage groove means;
Figure 39 is a top view of an embodiment of a slab F;
Figure 40 is a side view of the slab of figure 39 showing the cleavage groove means;
Figure 41 is a top view of an embodiment of a slab G;
Figure 42 is a side view of the slab of figure 41 showing the 21~03~7 cleavage groove means;
Figure 43 is a perspective view of a slab D shown beside the three blocks K, Km and L obtainable therefrom;
Figure 44a is a perspective view of a slab E shown beside 5the two blocks N and O obtainable therefrom;
Figure 44b is a perspective view of a slab E shown beside the three blocks K, M and L obtainable therefrom;
Figure 45a is a perspective view of a slab F shown beside the two blocks Q and O obtainable therefrom;
10Figure 45b is a perspective view of a slab F shown beside the three blocks L, M and P obtainable therefrom;
Figure 46a is a perspective view of a slab G shown beside the two blocks R and S obtainable therefrom;
Figure 46b is a perspective view of a slab G shown beside the 15two blocks T and U obtainable therefrom;
Figure 47 schematically illustrates a side view of a stack of blocks from slabs D through G;
figure 48 illustrates a one-third block stacked on a one-half block obtained from blocks D to G;
20Figure 49 is a top plan view of a another filled mold for side casting of slabs D, E, F and G in accordance with the present invention;
Figure 50 is a diagrammatic representation of the front of a wall with four courses of blocks, each block being 25identified as to type;
Figure 51 is a diagrammatic representation of the front of a wall with eight courses of blocks, each block being identified as to type, the wall having a straight and a curved segment; and Figure 52 is a diagrammatic representation of the front of a wall with eight courses of blocks, each block being identified as to type.

In the description which follows surfaces will be described as being planar. It is to be understood herein that a planar surface need not be smooth nor necessarily flat; a planar surface may, for example, be roughened.

Figures 1, 2 and 3 illustrate a slab 1 which may be broken into a first block and a second block in accordance with the present invention. The first block element is designated by the reference numeral 2 and the second block element is designated by the reference numeral 3; these same numerals will be used hereinafter with respect to other slabs to designate these same block elements.
The slab 1 has cleavage groove means which comprises opposed grooves 4 and 5 which are disposed on opposite sides of the slab. The grooves 4 and 5 are configured to provide a weak point or fault which facilitates the splitting of slab 1 along cleavage line or plane 6 into first and second blocks which are mirror images of each other. The separated first and second - 209û~87 blocks correspond in shape to the block elements 2 and 3 respectively; prior to splitting the front faces of the first and second blocks are joined along the cleavage line 6 such that the front surfaces of the first and second blocks are only exposed when the slab 1 is split along the cleavage line 6.
When split from each other the front surfaces of the first and second blocks are generally planar but may be relatively smooth or coarse in texture (see U.S. Patent no. 5,017,049).

Each of the block elements 2 and 3 also has a generally rectangular planar rear surface 7 and 8 respectively. The block elements 2 and 3 also have generally rectangular planar side surfaces 9 and 10 respectively which are in the same plane and which define a right angle with the front faces thereof joined along cleavage line 6. The generally rectangular planar side surfaces 11 and 12 which are opposite to sides 9 and 10, each respectively define an acute angle alpha and beta with the front faces thereof joined along cleavage line 6; the angle alpha and beta in the illustrated embodiment have the same value (i.e. 76 degrees); if desired, the values for the angles may be different. The rear surfaces 7 and 8 are generally parallel to the cleavage line 6 such that on splitting of the slab in two parts the front surface of the first and second block elements are generally parallel to the rear surfaces 7 and 8 respectively.

209~3~7 -The block elements have respective trapezoidal top surfaces 13 and 14 as well as respective trapezoidal bottom surfaces 15 and 16. The top and bottom surfaces are spaced apart by the body of each block and are generally planar and generally parallel;
S it is to be understood herein that the expression "generally parallel" is to include surfaces which while not perfectly parallel are substantially parallel or do not deviate from parallelism in any substantial way so as to interfere with the support role of the surfaces. The surfaces 13 and 15 as well as 12 and 15 give the first and second blocks a generally trapezoidal configuration, the side, front and rear surfaces thereof being of generally of rectangular configuration.

Each block element 2 and 3 has a flange or ridge member 17 and 18 respectively; the ridge members extend downwardly from the rear surfaces 7 and 8 and bottom surfaces 15 and 16; they also extend from one side surface 9 (or 10) to the other side surface 11 (or 12).

The planar top surfaces 13 and 14 are interrupted by grooves 19 and 20 respectively. These grooves are sized wider than the flanges to be received therein such that the flanges may be disposed therein in angled relation i.e. the grooves are sized so as to be able to receive a flange transversely with respect to the longitudinal axis of the groove. Grooves 19 and 20 are thus sized so that a flange of the third, fourth or fifth block (described below) may be received therein so as to facilitate interlocking of these (crown) blocks so that they may be offset forwardly (i.e. project forwardly) with respect to the retainer wall surface rather than be rearwardly offset top.

The blocks 2 and 3 also have a ridge member 21 and 22 respectively which define a side wall of groove 19 and 20 as well as define a rear edge part of the top surfaces 13 an 14.
The block elements also have a recess designated generally by the reference numerals 23 and 24. The recesses 23 and 24 are defined by abutment surfaces 23' and 24' and ledge or shoulder surfaces 23" and 24" respectively; the abutment surfaces are intended to engage the flanges of an overlying block for interlocking of the blocks in set back relation.

Turning to Figure 3, when looking at the separated blocks in the line of sight shown by the schematic representation of the respective eye, the first block (i.e. having top surface 13) is a right hand block and will sometimes be referred to 20 hereinafter as block BR; the acute angle alpha is on the right side of the exposed front face of the first block. On the other hand, the second block (i.e. having top surface 14) is a left hand block and will sometimes be referred to hereinafter as block B~; the acute angle beta is on the left side of the 25 exposed front face of the second block.

Figures 4, 5 and 6 illustrate a slab 25 which may be broken into a first block 2 and a fifth block 26 in accordance with the present invention; the elements of the first block element are the same as those described above with respect to figures 1 to 3 so the same numerals as used with respect to figures 1 to 3 denote the various parts of block element 2.

The slab 25 has cleavage groove means which comprises opposed grooves 27 and 28 which are disposed on opposite sides of the slab. The grooves 27 and 28 are configured to facilitate the splitting of slab 25 along cleavage line or plane 29 into first and fifth blocks. The separated first and fifth blocks correspond in shape to the block elements 2 and 26; prior to being split apart, the front faces of the first and fifth blocks are joined along the cleavage line 27 such that the front surfaces of the first and fifth blocks are only exposed when the slab 25 is split along the cleavage line 29. When split from each other the front surfaces of the first and third blocks are generally planar but may be relatively smooth or coarse in texture as mentioned above.

The fifth block element 26 also has a generally planar rear surface 7 and 30 respectively. The block elements 2 and 26 also have planar side surfaces 9 and 31 respectively which are in the same plane and which define a right angle with the front faces thereof joined along cleavage line 29. The planar side ~09~3~7 surfaces 11 and 32 are opposite to side surfaces 9 and 31; the surfaces 31 and 32 are generally parallel to each other whereas the side surface 30 is generally parallel to the cleavage line 29 such that on splitting of the slab in two parts the front surface of the fifth block element is generally parallel to the rear planar surface 30.

The fifth block element 26 has a planar top surface 33 as well as a planar bottom surface 34 which intersect the other (side and rear) surfaces; the top and bottom surfaces are spaced apart by the body of the third block. The front face defined by cleavage line 29 and the surfaces 30, 31 and 32 give the third block a generally rectangular configuration; i.e. the top, the bottom, the sides, and the front and rear surfaces thereof have a generally rectangular configuration. The fifth block element is sometimes hereinafter referred to as block C.

The block element 26 has a flange or ridge member 35; the ridge members extend downwardly from the rear surfaces 31 and the bottom surface 34; the ridge member 35 also extends from one side surface 31 to the other side surface 32. This ridge member 35 is intended to be received in a groove 19 or 20 of the first and second block elements or in a recess 23 or 24 thereof.

Figure 6 shows the block elements of slab 25 split apart.

.20~q387 Figures 7, 8 and 9 illustrate a slab 36 which may be broken into a second block and a fifth block in accordance with the present invention. The second block element is designated with the numeral 3 and the fifth block element is designated by the reference numeral 26. These block elements are as described above so the same reference numerals are used to designate the same features.

The slab 36 has cleavage groove means which comprises opposed grooves 37 and 38 which are disposed on opposite sides of the slab. The grooves 37 and 38 are configured to provide a weak point or fault which facilitates the splitting of slab 36 along cleavage line or plane 39 into second and third blocks. As in the case of slabs 1 and 25, prior to being split apart, the front faces of the second and third blocks are joined along the cleavage line 39 such that the front surfaces of the first and second blocks are only exposed when the slab 36 is split along the cleavage line 39; as mentioned above when split from each other the blocks are generally planar but may be relatively smooth or coarse in surface texture (see U.S. Patent no.
5,017,049).

Figure 9 shows the block elements of slab 36 split apart.

Figures lO and 11 illustrate a slab 40 which may be broken into a fifth block and a fourth block in accordance with the present 20~0387 invention. The fifth block element is designated with the numeral 26 and the fourth block element is designated by the reference numeral 41. The fifth block element 26 is as described above so the same reference numerals are used to designate the same features. Although somewhat smaller, the fourth block 41 has generally the same configuration as the second block element 3 so that the same reference numerals are used to designate the common features;i.e. it is a left hand block and is sometimes referred to hereinafter as block CL.
The block element 41 differs, however, from the block element 3 in that it does not have the groove 20, the ridge 22 nor the recess 24; additionally the width (from front surface to rear surface) of the block element 41 is smaller (e.g. by 6 mm) than the corresponding width of the first and second block elements, the flange 18' is narrower than the flange 18; the angle beta is the same as mentioned above i.e. 76 degree. The width (from front surface to rear surface) of the fourth block is the same as that of the fifth block element.

The slab 40 also has cleavage groove means which comprises opposed grooves 42 and 44 which are disposed on opposite sides of the slab; the slab 40 is splittable along cleavage line 45.

Figures 12 and 13 illustrate a slab 46 which may be broken into a third block and a fifth block in accordance with the present invention. The fifth block element is designated by the reference numeral 26 and the third block element is designated with the reference numeral 47. The fifth block element 26 is as described above so the same reference numerals are used to designate the same features. Although somewhat smaller, the third block 47 has generally the same configuration as the first block element 2 so that the same reference numerals are used to designate the common features;i.e. it is a right hand block and is sometimes referred to hereinafter as block CR.
The block element 47 differs, however, from the block element 2 in that it does not have the groove 19, the ridge 21 nor the recess 23; additionally the width (from front surface to rear surface) of the block element 47 is smaller (e.g. by 6 mm) than the corresponding width of the first and second block elements, the flange 17' is narrower than the flange 17; the angle alpha is the same as mentioned above i.e. 76 degrees. The width (from front surface to rear surface) of the third block is the same as that of the fifth block element.

The slab 46 has cleavage groove means which comprises opposed grooves 47 and 48 which are disposed on opposite sides of the slab; the slab 46 is splittable along cleavage line 49.

The flanges of all of the blocks referred to above are sized with respect to the recesses 23 and 24 such that, when a block is placed over a first or second block, a flange will horizontally abut the underlying first or second blocks but 2~90387 will not vertically rest on the shoulder defined by the recesses 23 and 24 of the underlying first or second blocks.
When in the recess a flange may be considered to be used as set backward means for interlocking and setting backward the blocks a predetermined distance with respect to the underlying block.
The predetermined distance may be determined in known manner and will vary with the relative widths (from front surface to rear surface) of the blocks as well as the width or thickness of the flanges, etc.. The predetermined setback distance may for example be up to 25 mm or less for the above mentioned blocks.

The flanges of the third, fourth and fifth blocks are sized smaller than the depth of the grooves 19 and 20 such that when a flange is disposed in a groove 19 or 20 it does not touch the bottom of the groove; normally the flange will however, rest up against (i.e. abut) the front side surface of the groove. When in the groove the flanges may be considered to be used as set forward means for interlocking and setting forward of the third fourth and fifth blocks a predetermined distance with respect to the underlying block. The predetermined distance may be determined in known manner and will vary with the position and width of the grooves, the relative widths (from front surface to rear surface) of the blocks as well as the width or thickness of the flanges. The predetermined setforward distance may for example be from 25 mm to 100 mm for the above 2~so3~7 mentioned blocks.

The flanges of the third, fourth and fifth blocks are also narrower than the flanges 17 and 18 so as to take into account that these blocks are smaller in width from front surface to rear surface than the first and second blocks; in the illustrated embodiments the width of the flanges for the first and second blocks (e.g. 18 mm) is greater than the width of the flanges for the third, fourth and fifth blocks (e.g. 12 mm) by an amount which corresponds to the difference in width (from the front to rear surface) of the first and second blocks relative to the other blocks.

Turning to figures 14 and 15, they illustrate a (second) slab 50 which may be broken into a first block and a fourth block in accordance with the present invention. The first block element is designated by the reference numeral 2 and the fourth block element is designated with the reference numeral 41. The first and fourth block elements are as described above so the same reference numerals are used to designate the same features.
The slab 50 has a cleavage plane or line 51.

Turning to figures 16 and 17, they illustrate a (third) slab 52 which may be broken into a second block and a third block in accordance with the present invention. The second block element is designated by the reference numeral 3 and the third 20~0~87 block element is designated with the reference numeral 47. The second and third block elements are as described above so the same reference numerals are used to designate the same features. The slab 52 has a cleavage plane or line 53.

Turning to figures 18 and 19, they illustrate a (eighth) slab 54 which may be broken into a third block and a fourth block in accordance with the present invention. The third block element is designated by the reference numeral 47 and the fourth block element is designated with the reference numeral 41. The third and fourth block elements are as described above so the same reference numerals are used to designate the same features.

The slab 54 has a cleavage plane or line 55. As may be seen form figure 18, the third and fourth blocks as in the case of the first and second block elements are mirror images of each other; the third block being a third right hand block and the fourth block element being a fourth left hand block.

Turning to figures 20 and 21, they illustrate a (ninth) slab 56 which may be broken into two fifth blocks in accordance with the present invention. The fifth block elements are designated by the reference numeral 26. The fifth block elements are as described above so the same reference numerals are used to designate the same features. The slab 56 has a cleavage plane or line 57.

20so~7 The blocks of the present invention may be used to provide a retaining wall having a more or less continuous surface. The first and second blocks may be used to build up the body of the retaining wall (whether curved or straight). The third and fourth blocks may be used to cap the top of the retaining wall (whether curved or straight) but may also be used to build up the body of the retaining wall, i.e. they compliment the first and second blocks. The fifth block may be used to cap the top of a (straight) retaining wall but may also be used to build up the body of the retaining wall.

Figures 22, 23 and 24 show in schematic form the use of the fifth (or third or fourth) block either as a cap element or as a part of the body of a retaining wall. The crown block designated 58 in these figures may be a third, fourth or fifth block as desired; the other blocks may be selected from the first and second blocks for a convexly curved surface. For example, the first and second blocks may be applied in alternating layers and the wall may finally be capped or crowned with a layer of third or fourth blocks. The front face of the retaining wall is indicated generally by the reference numeral 59. The block 58 is shown in figure 22 in a forward extending position relative to the underlying block; in figure 23 the block 58 is shown in a rearwardly or set back position relative to the underlying block.

Figure 25 illustrates a layer of second blocks 59 overlaying a layer of first blocks 60; the second layer being partly covered by fourth blocks 61 to cap the stack of blocks, the fourth blocks being set forward with respect to the underlying second block layer.

Figure 26 illustrates the angular disposition of the flanges 18' of the fourth blocks 61 in the grooves 20 of the second blocks; i.e. for curved courses of the blocks. As may be seen the width of the grooves is sufficient to accommodate this type of angular positioning of the flanges 18'. Thus, the width of the grooves is selected with the angular disposition in mind.
The grooves may for example be from 20 mm to 50 mm in width.

Figure 27 schematically illustrates a wall construction using rectangular shaped retaining wall blocks; the wall is seen from above so as to expose a layer of blocks in the body of the wall. The wall has a convex outer surface designated generally by the numeral 62 and a concave outer surface designated generally by the reference numeral number 63. As may be seen the convex outer surface is discontinuous in the sense that cavities 64 are defined between the blocks. The concave outer surface on the other hand presents a more or less continuous outer surface free of such cavities.

Figure 28 schematically illustrates a wall construction using blocks in accordance with the present invention; the wall is seen from above so as to expose a layer of second blocks 59 (only one of which is identified by the reference numeral 59) in the body of the wall. The wall has a convex outer surface designated generally by the numeral 65 and a concave outer surface designated generally by the reference numeral number 66; the wall also has a straight portion 67. As may be seen the convex outer surface 65 is continuous in the sense that no cavities are defined between the blocks 59; the concave outer surface also presents a more or less continuous outer surface free of such cavities. The radius of curvature for the concave and convex surfaces are designated by the reference numerals 68 and 69. The minimum value for the radius of curvature 68 will depend on the angle beta chosen for the second blocks as well as the size of the face surfaces. Preferably the angles alpha and beta have the same values.

If a kit is provided with slabs (either exclusively or in addition to separate blocks), the slabs have to be split into the two constituent blocks thereof before the blocks may be incorporated into a retaining wall. A slab may be split in any (known) manner which provides the desired front surface; i.e.
by methods known in the art.

In order to construct a retaining wall using blocks of the present invention usual precautions must of course be taken with respect to proper preparation of the foundation under the blocks, etc.

A plurality of slabs in accordance with the present invention may advantageously be formed by exploiting a (known) molding or casting technique wherein the slabs are cast on one of their sides; such a technique is described, for example, in U.S.
patent no. 5,017,049.

In accordance with the side molding process, casting of a slab may be accomplished by using a compression head in conjunction with a multi-part mold.

The mold may, for example, comprise a wall part separable from a bottom part. The wall part may have a plurality of open ended hollow chambers each having upper and bottom openings.
Each hollow chamber may have a plurality of side walls between the openings for defining the body of the slab. Two opposed side walls of each chamber have surfaces configured to provide the slab with top and bottom surfaces each of which has an inset groove defining the junction (of the front surfaces) of the two separate blocks and along which the slab may be split prior to use.

The mold bottom part during casting closes off the bottom - 209038 t openings of the wall mold part so as to provide a plurality of mold cavities. The mold bottom part has a surface configured to impart to the slab side along which the slab is cast, a generally planar surface such that when the wall part is separated for the cast block, the cast block is able to stand alone along the side of the slab on the bottom part which may double as a palate for initial transport and storage of the cast slabs; i.e. the slab is cast on one of its sides wherein the surfaces of the separate blocks making up the slab are generally in the same plane.

The compression head may have a compression surface which imparts to the side surface of the slab opposite to that on which the slab is cast, the desired parallel or non-parallel surface characteristics. Thus for example to form a slab breakable into a first and second block it may have a surface split into two parts at the middle thereof; each part may, for example, extend at a downward angle from the middle of the head so as to cast first and second blocks having a side surface defining an acute angle with the front surfaces; alternatively, for example, one part of the surface of the compression head may extend from the middle of the head parallel to the opposite bottom surface whereas the other part may extend from the middle at an angle so as to form a first block attached along the cleavage groove to a third block; and so on for the other blocks.

2090~387 Figure 29 illustrates a top view of a filled mold 70. The mold cavities shown allow for the simultaneous preparation of first (e.g. cavity 71), fourth (e.g. cavity 72), fifth (e.g. cavity 73), sixth (e.g. cavity 74) and seventh (e.g. cavity 75) slabs;
the mold furnishes twelve (120 first, twelve (12) second, six (6) third, six (6) fourth and eighteen (18) fifth blocks sufficient for a wall kit for making a wall (segment) having three courses of blocks with a flat surfaced crown course.

The wet mix in the mold 70 is cast by applying pressure to the mix at the open upper end of the mold using a compression head of appropriate surface configuration to obtain the desired two part slabs. The compression head acts on the exposed surface of the mix.

Any suitable wet mixture for forming a concrete slab may for example be used in the casting process; see U.S. patent no.
5,017,049 for example mixtures.

Turning to figures 30 and 31, these figures show diagrammatically how the 54 blocks obtained from the mold shown in figure 29 may be used to make a wall having three courses.
For the purposes of illustration the blocks are shown as resting directly over an underlying block; in use however it is preferable for the blocks to overlap two underlying blocks as shown in figure 34.

209~387 For figures 30 and 31, the 54 blocks are given their previously referred to designations with reference to blocks shown in the previously described figures, namely C designates a fifth rectangular block (18 thereof);
CR designates a third right hand block (6 thereof);
CL designates a fourth left hand block (6 thereof);
BR designates a first right hand (grooved) block (12 thereof); and BL designates a second left hand (grooved) block (12 thereof).

Referring to figure 30 this figure represents a wall made of the above referred to blocks the wall being straight over its entire length as indicated by the arrow 80. As may be seen the crown course of block consists of fifth rectangular blocks; the middle row comprises a mixture of first and second blocks; and the third row comprises second, third and fourth blocks. Since the middle row consists of grooved blocks as described herein the crown course of blocks may be offset rearwardly or forwardly as desired.

Figure 31 on the other hand shows a wall made of the same blocks from the mold shown in figure 29 but so arranged as to provide a wall having a straight portion 81 and a curved portion 82. Thus the crown course of blocks for the straight portion consists of fifth blocks C; the other curved half of 2~387 the wall has a crown course of blocks which comprises third and fourth blocks. The middle course of blocks comprises first and second blocks so that the crown course may be offset rearwardly or forwardly as desired.

Provided that the adjacent blocks of the crown courses of the walls shown in figures 30 and 31 abut along their side surfaces the crown courses present a relatively flat uninterrupted top surface. Although such flat surface is preferred for aesthetic reasons, a kit may be configured if desired so as to provide a top surface which may be interrupted by openings.

Turning to figures 32 and 33 in these figures show walls having three course of blocks. The wall again is made from a kit comprising 54 blocks which are given their previously referred to designations with reference to blocks shown in the figures.
The proportion of the blocks is, however, different from that of the kit used with respect to the wall shown in figures 30 and 31, namely C designates a fifth rectangular block (12 thereof);
CR designates a third right hand block (6 thereof);
C~ designates a fourth left hand block (6 thereof);
BR designates a first right hand (grooved) block (15 thereof); and BL designates a second left hand (grooved) block (15 thereof).

2~90387 The wall represented by figure 31 has a crown composed of fifth and third blocks; the middle row comprises first and second blocks. Accordingly, the wall may be entirely straight as shown by the arrow 83 or else it may have straight portion 84 and a curved portion 85, the curved portion representing about one third of the length of the wall. The crown course of the wall in figure 32 will have rearwardly extending openings or spaces between adjacent tapered third blocks.

If the fourth blocks of the wall shown in figure 32 are used to replace the fifth blocks adjacent to the third blocks then as shown in figure 33 the wall may have a straight portion 86 and a curved portion 87, the curved portion representing about two thirds of the length of the wall.

Turning to figure 34, this figure shows a straight portion of wall made in accordance with the present invention. The crown row is offset forwardly and comprises tapered and rectangular blocks, the blocks being identified with the above referred to designations. Preferably, however, for a predetermined number of courses of blocks the crown course for straight walls consists of rectangular fifth blocks, i.e. the number of rectangular blocks in a kit is sufficient to meet this criteria (e.g. the kit used for the wall shown in figures 30 and 31).
The portion of the wall comprising the tapered block elements such as the first, second, third and fourth blocks can be 2090~87 converted into a curved portion by reducing the spaces (some of which is designated by the reference numeral 88) between the side surfaces thereof right up to and including the case wherein the sides abut each other. The larger space 89 represent the space between adjacent first and second blocks wherein the adjacent faces of the blocks both define an acute angle.

In order to produce a wall having more than three courses of blocks a plurality of kits as obtainable from the mold shown in figure 29 may be used.

Figures 35, and 36 illustrate a slab D indicated generally by the reference number 90. The slab 90 may be broken into three blocks K, Km and L, the corresponding block elements of which are designated respectively by the reference numbers 91, 92 and 93.

The slab 90 has a first cleavage groove means which comprises opposed grooves 94 and 95 which are disposed on opposite sides of the slab. The grooves 94 and 95 are configured to provide a weak point or fault which facilitates the splitting of slab 90 along cleavage line or plane 96 so as to liberate block K
therefrom.

The slab 90 also has a second cleavage groove means which 2~90~87 comprises opposed grooves 97 and 98 which are disposed on opposite sides of the slab. The grooves 97 and 98 are configured to provide a weak point or fault which facilitates the splitting of slab 90 along cleavage line or plane 99 so as to liberate block L therefrom.

The slab 90 has generally rectangular planar end surfaces 100 and 101 respectively. The slab 90 also has rectangular planar side surface portions 102, 103 and 104 respectively which are in the same plane and which define a right angle with the cleavage lines 96 and 99. The slab further includes generally rectangular planar side surface portions 105, 106 and 107 which are opposite to the side surface porions 102, 103 and 104 respectively. The side surface portions 102 and 103 are generally parallel to the opposed side surface portions 105 and 106. On the other hand the side surface portion 107 defines an acute angle beta with the second cleavage means. The end surfaces 100 and 101 are generally parallel to the cleavage lines 96 and 99 such that on splitting of the slab the liberated surfaces (front or rear) are generally parallel to the end surfaces 100 and 101 respectively.

The block elements 91 and 92 have respective rectangular top and bottom surfaces 108, 109, 110 and 111. The element 93 has respective trapezoidal top and bottom surfaces 112 and 113.
The top and bottom surfaces are spaced apart by the body of each block and are generally planar and generally parallel.

Each block element 91, 92 and 93 has a flange or ridge member 114, 115 and 116 respectively; the ridge members extend downwardly from the rear surfaces of a corresponding block (e.g. surfaces 100 and 101) as well as from bottom surfaces 109, 111 and 113; they also extend from one side surface portion to the other opposed side surface.

The planar top surface of element 93 is interrupted by offsetting grooves 117 and 119, these grooves being separated by a projection 120 which defines a part of the top surface of the element 93. The groove 119 is also bordered by the projection 121. The groove 119 is for example sized to receive a flange such as flange 114 so that the flange may be disposed therein in angled relation i.e. the groove is sized so as to be able to receive a flange transversely with respect to the longitudinal axis of the groove. Both of grooves 117 and 119 may, if desired be sized so that a flange of a block K, Km or P
(as described herein) may be received therein so as to facilitate interlocking of these (crown) blocks so that they may be offset forwardly (i.e. project forwardly) with respect to the retainer wall surface rather than be rearwardly offset with respect to the underlying block.

Turning to figures 37 and 38, these show a slab E indicated 2090~87 generally by the reference number 123. Slab 123 is essentially the same as slab 90 except that it has a third cleavage groove means. Accordingly, the same reference numerals are used to designate the common elements.

The third cleavage groove means comprises opposed grooves 124 and 125 which are disposed on opposite sides of the slab 123.
The grooves 124 and 125 are configured to provide a weak point or fault which facilitates the splitting of slab 123 along cleavage line or plane 126. As a result the slab 123 comprises a variety of additional block elements including elements 127, 128 and 129 (i.e. corresponding to blocks M, N and O
respectively).

Slab 123 also includes an elongated notch 130 extending the length of flange 115 for facilitating removal of the flange if a block O is desired; i.e. by breaking off the flange 115 in any suitable manner.
Turning to figures 39 and 40, these show a slab F indicated generally by the reference number 131. Slab 131 is essentially the same as slab 123 except that it has a second trapezoidally shaped element 132 instead of a rectangularly shaped element 91. Accordingly, the same reference numerals are used to designate the common elements.

The side surface portion 105 for element 132 defines an angle ~ .

alpha with the cleavage line 96; i.e. the top and bottom surfaces 108 and 109 have a trapezoidal aspect. As a result the slab 132 comprises an additional block element 133 (i.e.
corresponding to blocks Q).

Figures 41 and 42 illustrate a slab G which is designated by the numeral 135 which may be broken into a block R and a second block S, the corresponding block elements are designated by the reference numbers 136 and 137. The blocks R and S may also be subdivided into blocks T and U and respective block fragments, the corresponding block elements are designated by the reference numerals 138, 139, 140 and 141.

The slab 135 has cleavage groove means which comprises opposed grooves 142 and 143 which are disposed on opposite sides of the slab. The grooves 142 and 143 are configured to provide a weak point or fault which facilitates the splitting of slab 135 along cleavage line or plane 144 into blocks R and S which are mirror images of each other. The separated blocks R and S
correspond in shape to the block elements 136 and 137 respectively; prior to splitting the front faces of the blocks R and S are joined along the cleavage line 144 such that the front surfaces blocks R and S are only exposed when the slab 135 is split along the cleavage line 144. When split from each other the front surfaces of the blocks are generally planar but as mentioned above may be relatively smooth or coarse in 209~387 texture.

Each of the block elements 136 and 137 also has a generally rectangular planar rear surface 145 and 146 respectively. The block elements 136 and 137 also have generally rectangular planar side surfaces 138 ' and 139 ' respectively which are in the same plane and which define a right angle with the front faces thereof joined along cleavage line 144. The generally rectangular planar side surfaces 140 and 141 which are opposite to sides 138 ' and 139 ', each respectively define an acute angle alpha and beta with the front faces thereof joined along cleavage line 144; the angle alpha and beta in the illustrated embodiment have the same value (e.g. 75 degrees); if desired, the values for the angles may be different. The rear surfaces 145 and 146 are generally parallel to the cleavage line 144 such that on splitting of the slab in two parts the front surface of the blocks R and S are generally parallel to the rear surfaces 145 and 146 respectively.

The block elements have respective trapezoidal top surfaces 147 and 148 as well as respective trapezoidal bottom surfaces 149 and 150. The top and bottom surfaces are spaced apart by the body of each block and are generally planar and generally parallel. The top and bottom surfaces give the blocks R and S
a generally trapezoidal configuration, the side, front and rear surfaces thereof being of generally of rectangular 2û90387 configuration.

Each block element 138 and 139 has a flange or ridge member 149 and 150 respectively; the ridge members extend downwardly from the rear surfaces 145 and 146 and bottom surfaces 149 and 150;
they also extend from side surface to opposite side surface.

The bottom surfaces of the elements 136 and 137 are also interrupted by flanges 151 and 152. Elongated notches 153 and 154 extend the length of the flanges 151 and 152; these notches as in the case of similar notches referred to above are sized to facilitate the removal of the flanges 151 and 152 if blocks R and S are desired.

The flanges 151 and 152 may serve as the analogous end flanges for the blocks T and U, i.e. when the block fragment elements are removed. In this respect the block elements 136 and 137 are each provided with additional cleavage group means for allowing the terminal elements 140 and 141 to be split away so as to expose the rear surfaces of the blocks T and U, these blocks are also mirror image of each other. The additional cleavage groove means for the block element 136 comprises opposed elongated notches 153 and 155 which are configured to provide a weak point or fault which facilitates the splitting away of the fragment along cleavage line or plane 156. The additional cleavage groove means for the block element 137 209û387 comprises opposed elongated notches 154 and 157 which are configured to provide a weak point or fault which facilitates the splitting away of the respective fragment along cleavage line or plane 158.

The planar top surfaces 147 and 148 are each interrupted by two grooves adjacent the rear surfaces 145 and 146, namely grooves 159 and 160 on one hand and on the other hand grooves 161 and 162. Grooves 160 and 162 are sized wider than the flanges to be received therein such that the flanges may be disposed therein in angled relation i.e. the grooves are sized so as to be able to receive a flange transversely with respect to the longitudinal axis of the groove. Grooves 160 and 161 are thus sized so that a flange of a block (e.g. block P or K) may be received therein so as to facilitate interlocking of these (crown) blocks so that they may be offset forwardly (i.e.
project forwardly) with respect to the retainer wall surface rather than be rearwardly offset top. The grooves 159 and 161 may if desired be likewise so sized but are to be at least sized so as to longitudinally receive a flange. The elements 136 and 137 also have projections 163 and 164 respectively which each define a portion of the top surfaces thereof.

For the blocks obtainavble from the slabs D to G, the predeteremined setback may, for example, be up to 50 mm or less; hte predetermined setforward distance may, for example, 20903~7 be 25 mm to 100 mm; and the width of the setforward groove may, for example, be 22 mm to 100 mm.

Turning to figures 43 to 46b, these illustrate various combinations of blocks that may be obtained from slabs D
through G by the user of a kit comprising such slabs.

Figure 43 shows the exposed front surfaces 165 and 166 of blocks K and Km; as well as the exposed rear surface 167 of block Km and the exposed front surface 168 of block L.

Figure 44a shows the exposed front surfaces 169 and 170 of blocks N and O.

Figure 44b shows the exposed front surfaces 171 and 172 of blocks K and M; as well as the exposed rear surface 173 of block M and the exposed front surface 174 of block L.

Figure 45a shows the exposed front surfaces 175 and 176 of blocks Q and O.

Figure 45b shows the exposed front surfaces 177 and 178 of blocks P and M; as well as the exposed rear surface 179 of block M and the exposed front surface 1$0 of block L.

Figure 46a shows the exposed front surfaces 181 and 182 of 209~387 blocks R and S.

Figure 46b shows the exposed front surfaces 183 and 184 of blocks T and U; as well as the exposed rear surfaces 185 and 186 of blocks T and U.

The blocks K, Km~ L, M, P, T and U may each represent one third of the overall length of a respective slab from which the blocks are separated; they may for example all be of the same length. The blocks N, O, Q, R and S may each represent one half of the length of a respective slab from which they are separated; they may for example all be of the same length.

Turning to figures 47 and 48, these illustrate the advantageous stacking of the one-third and one-half blocks obtainable from the slabs D through G. As may be seen the lower most courses of blocks may comprise long blocks such as block O (i.e.
heavier one -half blocks) while upper courses of blocks may comprise shorter blocks such as blocks K and L (i.e. lighter one-third blocks); in this manner the heavier blocks support the greater weight of earth at the foot of the retainer wall whereas the lighter blocks can be placed at upper levels where less weight is to be applied to the retainer wall.

The abutment surface (of a lower block) engaging the rear flange of an upper block may, for setback purposes, comprise 2~903~7 the rear surface of a block; alternatively, if a one-third block (e.g. block L) is placed over a one-half block (e.g.
block 0 or R), the flange of the one-third block may be received in a rear groove of the lower block and abut an opposed surface thereof. The stack of blocks shown in figure 47 show a crown block, setback relative to the underlying block. The flange 114 of block K abuts against the rear surface 101 of the block L. If desired the block K could be set forward by disposing the flange 114 in the groove 119 of block L.

Figure 49 illustrates a top view of a filled mold 187. The mold cavities shown allow for the simultaneous preparation of slabs D (e.g. 1 cavity 188), slab E (e.g. 4 cavities 189), slab F (e.g. 3 cavities 190) and slab G (e.g. 2 cavities 191); the mold furnishes sufficient slabs for a wall kit for making a wall (segment) having four courses of blocks with a flat surfaced crown course.

Figure S0 schematically shows a wall built with a kit produced from the mold of figure 49. The various blocks are designated using the reference letters referred to above; see for example figures 43 to 46b. The reference numeral 192 shows the wall as straight whereas the other reference numerals designate a wall portion which may be straight (193) and wall portion which may be curved (194), the latter exploiting trapezoidal like blocks.

2~90387 Figure 51 and 52 each schematically show a wall built with 3 kits produced from the mold of figure 49. The various blocks are again designated using the reference letters referred to above; see for example figures 43 to 46b.

Turning to figure 52 the reference numerals designate a wall portion which may be straight (196) and wall portion which may be curved (197), the latter exploiting trapezoidal like blocks.
The remaining (unused) blocks after the wall is made consist of 2 blocks L and one block K.

Turning to figure 53 the reference numeral 197 designates a straight wall. The remaining (unused) blocks after the wall is made consists of 4 blocks P.

Claims

1. A grooved block, for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in successive offset courses, said grooved block comprising a block body, and a block interlock member, said block body having relatively planar top and bottom support surfaces, said top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, said block interlock member extending from said planar bottom surface adjacent said rear surface, said block interlock member and said block body being configured such that when said grooved block is disposed on an underlying retaining wall block having a said block body, said interlock member is able to engage said rear surface of said underlying block for offsetting said grooved block rearwardly a predetermined distance with respect to said underlying block, said grooved block being characterized in that said block body has a groove interrupting said planar top surface adjacent said rear surface, and said groove is sized such that when an overlying retaining wall block, having a said block body and a said block interlock member, is disposed on said grooved block, said groove is able to engage said interlock member of said overlying block for offsetting said overlying block forwardly a predetermined distance with respect to said grooved block.

2. A grooved block as defined in claim 1 wherein said grooved block has a generally tapered configuration wherein said front and rear surfaces thereof are generally parallel to each other, said front surface being larger than said rear surface.

3. A grooved block as defined in claim 1 wherein said grooved block has a generally trapezoidal configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with said front and rear surfaces thereof, said other side surface defining a generally acute angle with said front surface thereof.

4. A grooved block as defined in claim 3 wherein said groove consists of a groove extending from one respective side surface of said block body to said other respective side surface thereof, wherein said block interlock member consists of a flange extending downwardly from said bottom surface adjacent said rear surface, said flange extending from one side surface to said other side surface of said block body and wherein said groove is sized so as to be able to receive said flange transversely with respect to said longitudinal axis of said groove.

5. A grooved block as defined in claim 3 wherein said grooved block is configured as a right hand block.

6. A grooved block as defined in claim 3 wherein said grooved block is configured as a left hand block.

7. A grooved block as defined in claim 3 wherein said acute angle is an angle of from 60 to 85 degrees.

8. A grooved block as defined in claim 3 wherein said acute angle is an angle of about 75 degrees.

9. In a method for the construction of a mortarless retaining wall wherein a plurality of blocks are laid down one over said other so as to define a plurality of successive offset courses of blocks, said wall including an upper crown course of blocks resting on an underlying lower course of blocks, said upper crown course and said underlying lower course of blocks each comprising a plurality of retaining wall blocks, each said retaining wall block comprising a block body, and a block interlock member, said block body having relatively planar top and bottom support surfaces, said top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, said block interlock member extending from said planar bottom surface adjacent said rear surface, said block interlock member and said block body of a retaining wall block being configured such that when said retaining wall block is disposed on an underlying block having a said block body, said interlock member of said retaining wall block is able to engage said rear surface of said underlying block for offsetting said retaining wall block rearwardly a predetermined distance with respect to said underlying block, the improvement wherein said blocks of said underlying lower course of blocks are configured relative to said blocks of said crown course so that blocks of said crown course may be offset forwardly or rearwardly relative to blocks of said lower course of blocks, wherein said lower course of blocks comprises a plurality of grooved retaining wall blocks, wherein said block body of each grooved retaining wall block has a groove interrupting said planar top surface adjacent said rear surface, and wherein said groove of a grooved retaining wall block is sized such that when an overlying block, of said crown course of blocks, is disposed on said grooved retaining wall block, said groove thereof is able to engage said interlock member of said overlying block for setting said overlying block forward a predetermined distance with respect to said grooved retaining wall block.

10. A method as defined in claim 9 wherein each of said grooved blocks has a generally tapered configuration wherein said front and rear surfaces thereof are generally parallel to each other, said front surface being larger than said rear surface.

11. A method as defined in claim 9 wherein each of said grooved blocks has a generally trapezoidal configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with said front and rear surfaces thereof, said other side surface defining a generally acute angle with said front surface thereof.

12. A method as defined in claim 11 wherein said groove consists of a groove extending from one side surface of said block body to said other side surface thereof, wherein said block interlock member consists of a flange extending downwardly from said bottom surface adjacent said rear surface, said flange extending from one side surface to said other side surface of said block body and wherein said groove is sized so as to be able to receive said flange transversely with respect to said longitudinal axis of said groove.

13. A method as defined in claim 11 wherein each of said grooved blocks is configured as a right hand block.

14. A method as defined in claim 11 wherein each of said grooved blocks is configured as a left hand block.

15. A method as defined in claim 11 wherein said acute angle is an angle of from 60 to 85 degrees.

16. A method as defined in claim 11 wherein said acute angle is an angle of about 75 degrees.

17. A kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, said wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and said wall including an upper crown course of blocks resting on an underlying lower course of blocks, said kit being characterized in that said kit comprises a plurality of grooved blocks and a plurality of other blocks each of said blocks comprising a block body, and a block interlock member, said block body having relatively planar top and bottom support surfaces, said top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, said block interlock member extending from said planar bottom surface adjacent said rear surface, said block interlock member and said block body of a said block being configured such that when a said block is disposed on an underlying said block, said interlock member thereof is able to engage said rear surface of said underlying block for offsetting said block rearwardly a predetermined distance with respect to said underlying block, each of said grooved blocks having a groove for receiving a said block interlock member, a said groove of a grooved block interrupting said planar top surface adjacent said rear surface thereof, and being sized such that a block interlock member of a said other block is engageable therein for interlocking therewith, and said grooved and other blocks each being configured such that when a grooved block underlies an overlying other block, said block interlock member of said overlying other block is engageable in said groove of said underlying grooved block and said front surface of said overlying other block is able to be offset forwardly relative to said front surface of said underlying grooved block, said number of said grooved and other blocks in said kit being such that said crown course of blocks is able to consist of said other blocks and said immediately underlying lower course of blocks is able to consist of said grooved blocks.

18. A kit as defined in claim 17 wherein said grooved blocks have a generally tapered configuration wherein said front and rear surfaces thereof are generally parallel to each other, said front surface being larger than said rear surface.

19. A kit as defined in claim 17 wherein said grooved blocks have a generally trapezoidal configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with said front and rear surfaces thereof, said other side surface defining a generally acute angle with said front surface thereof.

20. A kit as defined in claim 19 wherein said groove consists of a groove extending from one side surface to said other side surface of said block body, wherein said block interlock member consists of a flange extending downwardly from said bottom surface adjacent said rear surface, said flange extending from one side surface to said other side surface of said block body and wherein said groove is sized so as to be able to receive said flange transversely with respect to said longitudinal axis of said groove.

21. A kit as defined in claim 17 wherein each of said grooved blocks is configured as a right hand block.

22. A kit as defined in claim 17 wherein each of said grooved blocks is configured as a left hand block.

23. A kit as defined in claim 17 wherein said acute angle is an angle of from 60 to 85 degrees.

24. A kit as defined in claim 17 wherein said acute angle is an angle of about 75 degrees.

25. A kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, said wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and said wall including an upper crown course of blocks resting on an underlying lower course of blocks, said kit being characterized in that said kit comprises a plurality of grooved blocks a plurality of other blocks and a plurality of rectangular blocks each of said blocks comprising a block body, and a block interlock member, said block body having relatively planar top and bottom support surfaces, said top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, said block interlock member extending from said planar bottom surface adjacent said rear surface, said block interlock member and said block body of a said block being configured such that when said block is disposed on an underlying said block, said interlock member thereof is able to engage said rear surface of said underlying block for offsetting said block rearwardly a predetermined distance with respect to said underlying block, each of said grooved and other blocks having a generally trapezoidal configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with said respective front and rear surfaces thereof, and said other side surface defines a generally acute angle with said respective front surface thereof, each of said rectangular blocks having a generally rectangular configuration wherein said front and rear surfaces thereof are generally parallel to each other, said two side surfaces thereof are generally parallel to each other, and each of said side surfaces define a generally right angle with said front and rear surfaces thereof, each of said grooved blocks having a groove for receiving a said block interlock member, a said groove of a grooved block interrupting said planar top surface adjacent said rear surface thereof, and being sized such that a block interlock member of a said other block or rectangular block may be engaged therein for interlocking therewith, and said grooved, other and rectangular blocks being configured such that when a grooved block underlies an overlying other or rectangular block, said block interlock member of said overlying other or rectangular block is engageable in said groove of said underlying grooved block and said front surface of said overlying other or rectangular block is able to be offset forwardly relative to said front surface of an underlying grooved block, said number of said grooved, other and rectangular blocks in said kit being such that said underlying lower course of blocks is able to consist of said grooved blocks and said crown course of blocks is able to consist of blocks selected from said other blocks and said rectangular blocks provided that said crown course of blocks of said curved portion of said wall is able to consist of said other blocks, and said number of said grooved and other blocks in said kit being such that all of said courses of blocks below said crown course of blocks of said curved portion of said wall are able to consist of blocks selected from said grooved and other blocks.

26. A kit as defined in claim 25 wherein said groove consists of a groove extending from one side surface to said other side surface of said block body, wherein block interlock member consists a flange extending downwardly from said bottom surface adjacent said rear surface, said flange extending from one side surface to said other side surface of said block body and wherein said groove is sized so as to be able to receive said flange transversely with respect to said longitudinal axis of said groove.

27. A kit as defined in claim 25 wherein each of said grooved blocks is configured as a right hand block.

28. A kit as defined in claim 25 wherein each of said grooved blocks is configured as a left hand block.

29. A kit as defined in claim 25 wherein said acute angle is an angle of from 60 to 85 degrees.

30. A kit as defined in claim 25 wherein said acute angle is an angle of about 75 degrees.

31. A kit as defined in claim 26 wherein said grooved, other and rectangular bricks are present in said kit in a proportion of 4:2:3 respectively.

32. A kit as defined in claim 26 for use in said construction of a retaining wall comprising 3 courses of bricks.

33. A kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, said wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and said wall including an upper crown course of blocks resting on an underlying lower course of blocks, said kit being characterized in that said kit comprises a plurality of first right hand blocks a plurality of second left hand blocks a plurality of third right hand blocks a plurality of fourth left hand blocks and a plurality of fifth blocks, each of said blocks comprising a block body, and a block interlock member, said block body having relatively planar top and bottom support surfaces, said top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, said block interlock member extending from said planar bottom surface adjacent said rear surface, said block interlock member and said block body of a said block being configured such that when said block is disposed on an underlying said block, said interlock member thereof is able to engage said rear surface of said underlying block for offsetting said block rearwardly a predetermined distance with respect to said underlying block, each of said first, second, third and fourth blocks having a generally trapezoidal configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a right angle with said front and rear surfaces thereof and said other side surface defines a generally acute angle with said front surface thereof, said configuration of said first block being a mirror image of said configuration of said second block, said configuration of said third block being a mirror image of said configuration of said fourth block, each of said fifth blocks having a generally rectangular configuration wherein said front and rear surfaces thereof are generally parallel to each other, said two side surfaces thereof are generally parallel to each other, and each of said side surfaces define a generally right angle with said front and rear surfaces thereof, each of said first and second blocks having a groove for receiving a said block interlock member, a said groove of a first or second block interrupting said planar top surface of a respective block adjacent said rear surface thereof, and being sized such that a said block interlock member of said third, fourth or fifth blocks is engageable therein for interlocking therewith, and said first, second, third and fourth blocks being configured such that when a first or second block underlies an overlying third, fourth or fifth block, said block interlock member of said overlying third, fourth or fifth block is engageable in a said groove of said underlying first or second block and said front surface of said overlying third, fourth or fifth block is able to be offset forwardly relative to said front surface of an underlying first or second block said number of said first, second, third, fourth and fifth blocks in said kit being such that said underlying lower course of blocks is able to consist of blocks selected from said first and second blocks and said crown course of blocks is able to consist of blocks selected from said third, fourth and fifth blocks provided that said crown course of blocks of a curved portion of a wall is able to consist of blocks selected from said third and fourth blocks, and said number of said first, second, third and fourth blocks in said kit being such that all of said courses of blocks below said crown course of blocks of a curved portion of said wall are able to consist of blocks selected from said first, second, third and fourth blocks.

34. A kit as defined in claim 33 wherein said groove consists of a groove extending from one respective side surface to said other respective side surface thereof, wherein said block interlock member consists of a flange extending downwardly from said bottom surface adjacent said rear surface, said flange extending from one side surface to said other side surface of said block body and wherein said groove is sized so as to be able to receive said flange transversely with respect to said longitudinal axis of said groove.

35. A kit as defined in claim 34 wherein said acute angle is an angle of from 60 to 85 degrees.

36. A kit as defined in claim 34 wherein said acute angle is an angle of about 75 degrees.

37. A kit as defined in claim 32 characterized in that said kit comprises a plurality of first slabs a plurality of second slabs a plurality of third slabs a plurality of fourth slabs and a plurality of fifth slabs, each of said slabs having cleavage groove means for allowing breakage of each slab into two separate blocks, each of said first slabs is breakable along said cleavage groove means thereof into a said first block and a said second block, each of said second slabs is breakable along said cleavage groove means thereof into a said a first block and a said fifth block, each of said third slabs is breakable along said cleavage groove means thereof into a said a second block and a said fifth block, each of said fourth slabs is breakable along said cleavage groove means thereof into a said a third block and a said fifth block each of said fifth slabs is breakable along said cleavage groove means thereof into a said a fourth block and a said fifth block, each of said slabs is configured such that prior to breakage thereof into said respective separate blocks, a side surface of one respective block defining a right angle with said front surface thereof and a side surface of said other respective block defining a right angle with said front surface thereof are generally disposed in said same plane, and said front face of each separate block is exposable on breakage of said corresponding slab into two separate blocks.

38. A kit as defined in claim 37 wherein said acute angle is an angle of from 60 to 85 degrees.

39. A kit as defined in claim 37 wherein said acute angle is an angle of about 75 degrees.

40. A kit as defined in claim 34 wherein said first, second, third, fourth and fifth bricks are present in said kit in a proportion of 2:2:1:1:3 respectively.

41. A kit as defined in claim 40 wherein said kit comprises at least 18 fifth bricks.

42. A kit as defined in claim 34 wherein said first, second, third, fourth and fifth bricks are present in said kit in a proportion of 5:5:2:2:4 respectively.

43. A kit as defined in claim 42 wherein said kit comprises at least 12 fifth bricks.

44. A kit as defined in claim 34 for use in said construction of a retaining wall comprising 3 courses of bricks.

45. A kit as defined in claim 41 for use in said construction of a retaining wall comprising 3 courses of bricks.

46. A kit as defined in claim 43 for use in said construction of a retaining wall comprising 3 courses of bricks.

47. A kit as defined in claim 25 wherein said number of said grooved, other and rectangular blocks in said kit is such that said crown course of blocks for a straight wall or straight portion thereof is able to consist of said rectangular blocks and said crown course of blocks of a curved portion of said wall is able to consist of said other blocks.

48. A kit as defined in claim 33 wherein said number of said first, second, third, fourth and fifth blocks in said kit is such that said crown course of blocks for a straight wall or straight portion thereof of said fifth blocks and said crown course of blocks for a curved portion of a wall is able to consist of blocks selected from said third and fourth blocks.

49. A kit for use in the construction of a mortarless retaining wall wherein a plurality of blocks are stacked in a predetermined number of successive offset courses of blocks, said wall, over its length, being relatively straight or having a relatively straight portion and a relatively curved portion and said wall including an upper crown course of blocks resting on an underlying lower course of blocks, said kit being characterized in that said kit comprises one or more slabs D
a plurality of slabs E
a plurality of slabs F
and a plurality of slabs G, said slabs D, E, F, and G being present in said kit in a proportion of 1:4:3:2 respectively, slab D having first and second cleavage groove means for allowing breakage of slab D into a separate block K, a separate block Km and a separate block L, a front face of each separate block K and Km being exposable on breakage of said slab along said first cleavage groove means to separate said block K
therefrom, a rear face of said block Km and a front face of said block L being exposable on breakage of said slab along said second cleavage groove means to separate said block L
therefrom, slab E having first and second cleavage groove means for allowing breakage of slab E into a separate block K, a separate block L and a separate block M, said slab E including a third cleavage groove means disposed between said first and second cleavage groove means for allowing breakage of slab E into a separate block N and a separate block O, a front face of each of said blocks K and M being exposable on breakage of said slab along said first cleavage groove means to separate said block K
therefrom, a rear face of said block M and a front face of said block L being exposable on breakage of said slab along said second cleavage groove means to separate said block L
therefrom, a front face of each separate block N and O being exposable on breakage of said slab, along said third cleavage groove means, into said separate blocks N and O, slab F having first and second cleavage groove means for allowing breakage of slab E into a separate block L, a separate block M and a separate block P, said slab F including a third cleavage groove means disposed between said first and second cleavage groove means thereof for allowing breakage of slab F
into two separate blocks O and Q, a front face of each separate block P and M being exposable on breakage of said slab along said first cleavage groove means to separate said block P
therefrom, a rear face of said block M and a front face of said block L being exposable on breakage of said slab along said second cleavage groove means to separate said block L
therefrom, a front face of each separate block O and Q being exposable on breakage of said slab, along said third cleavage groove means, into said separate blocks O and Q, slab G having cleavage groove means for allowing breakage of slab G into a separate block R and a separate block S, said block R having another cleavage groove means disposed adjacent a rear end thereof for allowing breakage thereof into a separate block T and a block fragment, said block S having another cleavage groove means disposed adjacent a rear end thereof for allowing breakage thereof into a separate block U
and a block fragment, a front face of each separate block R and S being exposable on breakage of said slab, along said cleavage groove means, into said separate blocks R and S, a rear face of each respective block T and U being exposable on breakage of a respective block T and U along a respective other cleavage groove means to separate a respective block fragment therefrom, each of said separate blocks comprising a block body, and a block interlock member, said block body having relatively planar top and bottom support surfaces, said top and bottom surfaces being generally parallel to each other, a front surface, a rear surface, and two side surfaces, said block interlock member extending from said planar bottom surface adjacent said rear surface, said block interlock member and said block body of a said block being configured such that when said block is disposed on an underlying said block, said interlock member thereof is able to engage an abutment surface of said underlying block for offsetting said block rearwardly a predetermined distance with respect to said underlying block, each of said blocks K, Km, M and N having a generally rectangular configuration wherein said front and rear surfaces thereof are generally parallel to each other, said two side surfaces thereof are generally parallel to each other, and each of said side surfaces define a generally right angle with said front and rear surfaces thereof, each block M comprising a respective third cleavage groove means, each block N comprising a respective first cleavage groove means, each of said blocks R, S, T and U having a generally trapezoidal configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a generally right angle with said front and rear surfaces thereof and said other side surface defines a generally acute angle with said front surface thereof, said block O comprising a respective second cleavage groove means, said block Q comprising a respective first cleavage groove means, said blocks O and Q each having a configuration wherein said front and rear surfaces thereof are generally parallel to each other, one side surface defines a generally right angle with said front and rear surfaces thereof and said other side surface comprises a first surface portion and a second surface portion, said first surface portion extending from a respective cleavage groove means to said front surface such that said first surface portion and said cleavage groove means define a generally acute angle, said second surface portion extending from a respective cleavage groove means to said rear surface generally parallel to said other side surface, said configuration of block R being a mirror image of said configuration of block S, said configuration of block T being a mirror image of said configuration of block U, each of said blocks L, T and U having an offsetting groove for receiving a said block interlock member, a said offsetting groove of a block L, T and U
interrupting said planar top surface of a respective block adjacent said rear surface thereof, and being sized such that a said block interlock member of a block K, Km and P is engageable therein for interlocking therewith, and said blocks L, T, U, K, Km and P being configured such that when a block L, T, or U underlies an overlying block K, Km or P, said block interlock member of said overlying block K, Km or P is engageable in a said offsetting groove of said underlying block L, T or U and said front surface of said overlying block K, Km or P is able to be offset forwardly relative to said front surface of an underlying block L, T or U.