Background Retaining wall blocks are conventionally solid blocks made of concrete or similar materials and are heavy and expensive to transport to a job site where the retaining wall is to be built. It would be desirable to provide a retaining wall block in the form of a kit of components that is compact and relatively lightweight, and therefore inexpensive to transport, and that is assembled and filled at a job site.

Summary of Invention The invention provides a kit of components for assembly to form a hollow retaining wall block adapted to be filled at the job site with a fill material, such as gravel, sand or soil, and used in the construction of a retaining wall. The assembled blocks of the inven- tion are preferably adapted to be attached to geogrid of the type conventionally used in the construction of retaining walls.

According to a preferred embodiment of the invention, the block is six-sided and the kit of components comprises the six sides of the block, namely, a bottom member, a top member, a left side member and a right side member, a back side member and a front side member. Side connectors connect the left and right side members to the bottom member and to the top member. Back connectors connect

the back side member to the bottom member and to the top member.

Front connectors connect the front side member to the bottom member and to the top member. The kit includes mating engagement means on the top and bottom side members for engaging the block with other such blocks in vertically adjacent courses.

Preferably, the top side component is adapted for attach- ment of the block to a sheet of geogrid. The top component has a first portion adjacent to the front side at a first height above the bottom side and a second portion adjacent to the back side member at a second height above the bottom member, the second height being lower than the first height. The block has a plurality of projections on the second portion of the upper side of the top member adapted for engagement in apertures of a geogrid sheet, the projections having a height greater than the thickness of the geogrid sheet and the top of the projections being at a height above the bottom side of the assembled block equal to the first height.

Optionally, the front side member, or the back side member, may be formed integrally with the bottom member, forming a single L-shaped component.

Brief Description of Drainas Fig. 1 is a perspective view of a retaining wall block kit according to a first embodiment of the invention;

Fig. 2 is a perspective view of a retaining wall block assembled from the kit of Fig. 1; Fig. 3 is an end elevation view of the assembled block of Fig. 2; Fig. 4 is an end elevation view of two courses of blocks with a sheet of geogrid attached therebetween; and Fig. 5 is a perspective view of a retaining wall block kit according to a second embodiment of the invention.

Description Referring to Fig. 1, the kit of components for the retain- ing wall block comprises six basic components, namely, top member 10, bottom member 12, front side member 14, back side member 16, left side member 18 and right side member 20.

Bottom member 12 is a generally rectangular planar member with a channel 22 formed therein, extending from the left to the right side of the member. A pair of connectors 24 are positioned at the corners of the back edge 26 of the bottom member. They comprise an outer L-shaped plate 28 and an inner L-shaped plate 30 forming slot 32 therebetween, which is sized to snugly receive the back side member and the left and right side members. A second pair of connectors 34 is positioned at the left and right edges of the bottom member. Each such connector comprises an outer plate and an inner

plate forming a slot therebetween which is sized to snugly receive left and right side members 18,20. Bottom member 12 has a pair of spaced pins 36 adjacent its front edge 38, for connection to the front member 12 as discussed below.

Top member 10 has a first portion 40 adjacent to front edge 42 thereof, and a second portion 44 adjacent the back edge 46 thereof at a lower height than said first portion.

Ridge 48 extends across the upper side of top member 10 and is adapted to be received in channel 22 of a block in an upper course when the blocks are assembled and used in a retaining wall.

A pair of connectors 50 is positioned at the corners of the back edge 46 of the top member. They comprise an outer L-shaped plate 52 and an inner L-shaped plate 54 forming slot 56 therebetween.

A second pair of connectors 58 is positioned at the left and right edges of the top member. Each such connector comprises an outer plate and an inner plate forming a slot therebetween.

A plurality of projections 60 is positioned along the second portion 44 of the top member 10 in a row adjacent the rear edge 46 thereof. As shown in Fig. 3, depicting a side elevation of the block, the height H2 of the second portion 44 is less than the height H, of the first portion 40. The height H3 of the projections 60 above the second portion is such that H2 + H3 = Hl, i. e. the top surface of the

projection 60 is at the same height as the first portion 40 of the top member of the assembled block.

Top member 10 has a pair of spaced pins 62 (see Fig. 3) on its lower side adjacent its front edge 42 for connection to the front side member 14, as discussed below.

Front side member 14 has a pair of bores 64 extending from its. upper to its lower side, positioned to align with and receive pins 36,62 when the block is assembled.

Left and right side members 18,20 are generally rec- tangular, planar members having a bottom cut-out 66 adapted to fit around channel 22 of the bottom member, and top cut-out 68 adapted to fit around second portion 44 of the top member 10, when the block is assembled.

The block components of Fig. 1 are assembled as follows.

Back side member 16 is attached to bottom member 12 by fitting it into the back portion of slots 32 of connectors 24. Left and right side members 18,20 are similarly fitted into connectors 24 and 34, with cut-outs 66 fitting snugly around channel 22. Front side member 14 is placed on bottom member 12 with pins 36 fitting snugly into bore 64.

The adjacent edges of the sides, back and bottom members abut one another.

Prior to attaching the top member 10, the block is filled with fill material to give it sufficient weight to be suitable for use in a retaining wall. Gravel, sand, soil or other aggregates available at the job site can be used. The top member 10 is then attached, fitting pins 62 into bores 64 of the front side member 14, connectors 58 over sides 18,20 and connectors 50 over the corners of left and right sides 18, 20 and back side 16. The block 1 thus assembled is shown in Fig. 2.

The assembled blocks 1 are used in conjunction with geogrid in the following manner. A geogrid sheet is a perforated sheet structure with a plurality of rows of apertures therein. Referring to Fig. 4, after one or more courses of blocks are laid, and the earth is filled in back of them, a geogrid sheet 70 is attached to the upper course by placing the row of apertures that is adjacent an edge of the geogrid sheet over projections 60 of the blocks. The next course of blocks is then laid atop this course, in a conventional staggered arrangement, with each block in the upper course being supported by two adjacent blocks in the lower course. Ridge 48 of the blocks in the lower course engages with grooves 66 of the blocks in the upper course, a groove 66 of each block in an upper course engaging with two ridges 48, one from each of two adjacent blocks in the course below. As seen in Fig. 4, because the height of the first or front portion 42 of the top side of a block is equal to the combined heights of the second portion 44 and the projections 60, the bottom side 12 of a block in the upper course rests on the front portion 42 and on the projections 60 of the blocks in the lower course. The blocks in the upper course thus prevent the geogrid sheet from slipping off the

projections 60. The height of the projections 60 is greater than the thickness of the geogrid, so the geogrid fits between the courses of blocks without interfering with their fitting together.

A second embodiment of the retaining block kit is illus- trated in Fig. 5. The kit is the same as that illustrated in Fig. 1 except that the structure for attaching the front side member to the bottom member and to the top member differs from that in the first embodi- ment. Front side member 14'has a groove 15 in its lower side and a groove 16 in its upper side extending along the length of the member.

Bottom member 12'has a ridge 17 extending laterally across it adjac- ent its front edge 38' ; and top member 10'has a ridge 19 extending laterally across its lower side adjacent its front edge 42'. Ridges 19, 17 are sized and positioned to fit snugly into grooves 16,15 respect- ively when the components of the block are assembled, and attach the top member and bottom member to the front side member.

Block components according to the invention can be made of plastics material suitable for external use. They can also be made of concrete or other suitable materials. The front side member can be made of an aesthetically attractive material, if desired, such as wood, marble or stone and its outer face, which forms part of the face of the retaining wall, can be shaped, textured or ornamented. The back face of the blocks can be made of the same material as the front face, and have the same appearance, so the blocks can be used to build a free- standing wall, as for a fence or a noise barrier. Plastic components exposed to the light in a finished wall should be UV resistant.

The front member can optionally have a separate facing element that attaches thereto and forms the face of the block. For example, the facing element can attach to the front element by interfitting vertically-oriented keyways on the outer face of the front element and the inner face of the facing element. The facing element can be made of an aesthetically pleasing and durable material.

The front member or the back member can optionally be integral with the bottom member, forming a single L-shaped compo- nent, or they can be connected prior to shipping. Such L-shaped components can nest compactly for transport.

A top component without geogrid-retaining pins or an interfitting ridge can be provided to cap the top row of blocks in a wall.

In some applications, it is desirable to be able to plant bushes along the top edge of a retaining wall. For such uses, open top members can be provided for the top course of blocks, such members comprising a circumferential ring or frame which holds the sides together but which is open at the top for planting purposes. Drainage holes are provided in the sides of such top course blocks.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. For example, the block may have a shape

other than generally parallelepiped and have fewer or more than six sides; for example it may be pentagonal in plan view or any shape that adapts to use in a retaining wall. Numerous means may be used for holding the components together, such as bolts and other conventional attachment devices. Various of the components may be attached together by means of hinges.