FIELD OF THE INVENTION
This relates to the field of retaining walls and the blocks used to construct retaining walls.
Retaining walls have been traditionally constructed using natural stone, landscape timbers, masonry block, poured concrete or railroad ties. More recently, engineered concrete block retaining systems have been introduced to the market. Those systems, exemplified by U.S. Pat. No. 7,011,474 to MacDonald, do not use mortar to lock the individual blocks into position but rely instead on methods of locking blocks into position, including specially formed pins. These lock pins include a relatively small diameter body portion that fits into holes formed in the blocks that form a lower course of a retaining wall and a relatively large diameter head portion that sits on top of the block. The next course of block is laid such that the larger diameter head of the lock pin fits into grooves formed in the bottom of the blocks that form the next course of block. Thus, the lock pin secures the two courses together. Other engineered concrete block retaining systems are shown in U.S. Pat. Nos. Re. 34,314, and 4,914,876 (both to Forsberg); 5,294,216 (to Sievert); and 7,168,892 (to MacDonald).
BRIEF DESCRIPTION OF THE DRAWINGS
These products have become popular because they are easy to install, very durable, and can be used to create structurally sound retaining walls at great cost savings. We now describe a retaining wall block that eliminates the need for locking pins having a large diameter head and small diameter body and reduces the weight of the engineered retaining wall block while maintaining the structural integrity of the block and the retaining walls formed of such blocks.
FIG. 1 is a plan view of the top surface of a retaining wall block;
FIG. 2 is a plan view of the bottom surface of the retaining wall block illustrated in FIG. 1;
FIG. 3 is a perspective view of a retaining wall block;
FIG. 4 is a top view of three interlocked retaining wall blocks;
FIG. 5 is a partial front perspective view of a retaining wall built of retaining wall blocks; and
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTS
FIGS. 6A and 6B are top views of alternate ways of laying a first course of five retaining wall blocks.
Referring to FIGS. 1 to 3, an engineered retaining wall block 1 is shown. Block 1 is preferably made of pre-cast concrete, although other suitable materials may be substituted for the concrete. Block 1 has three integrally formed parts, a body 2, a neck 3 and a head 4. The neck 3 connects the body 2 to the head 4. The body 2, neck 3, and head 4 all extend between top surface 5 and a bottom surface 6. The top and bottom surfaces 5 and 6 form planes that are essentially parallel to one another. Once block 1 is installed as part of a retaining wall, the forward face 7 of body 2 remains visible as part of the wall.
The neck 3 and head 4 are formed to reduce the weight of block 1, while maintaining structural integrity and support. Body 2 forms the greatest part of block 1, with a width of approximately one and ½ feet and a depth of just over 4 inches. Neck 3 is long and narrow by comparison. Neck 3 is narrowed about 4 inches on each side of body 2 so as to remain centered on body 2 and to create shoulder portions 8 and 9 on each side of body 2. The cross-section of neck 3 is thus reduced to approximately half the cross-section of body 2. Neck 3 extends approximately five and ¾ inches in depth. The weight of neck 3 is further reduced by forming a rectangular-shaped opening 10 that extends through the neck 3 from the top surface 5 to the bottom surface 6 of block 1. Opening 10 is molded to be approximately 5 inches wide and 6 inches deep, and centered within neck 3. The forward-most wall 11 of opening 10 is approximately co-planar with shoulders 8 and 9.
First and second receiving openings 12 and 13 are formed in the body 2 and extend from the top surface 5 to the bottom surface 6. In the preferred embodiment, each of these openings is approximately one and ⅛ inches thick and 2¾ inches wide. The receiving openings 12 and 13 are wide and long enough to ease installation and to account for variations encountered on-site when laying a wall. The extension of receiving openings 12 and 13 through block 1 from the top surface 5 to the bottom surface 6 saves material costs and effectively reduces block weight so as to further ease placement and installation.
First and second pin holes 14 and 15 are formed in the body 2. These pin holes are approximately 9/16 inches in diameter and extend approximately 2½ inches into body 2. These pin holes are designed to accept insertion of pins which are used to interlock block 1 in position with one or more blocks placed above. Pin holes 14 and 15 are also formed to include clean out holes 31 and 32, respectively, which are of smaller diameter than the pin holes 14 and 15. In one embodiment, the clean out holes 31 and 32, shown in FIGS. 1-3, are 7/16 inches in diameter and are designed to avoid debris accumulation in pin holes 14 and 15. During installation, pins 16 and 17 are placed into pin holes 14 and 15. FIG. 3 shows the pins 16 and 17 inserted into block 1. Without clean out holes 31 and 32, debris can accumulate in the pin holes 14 and 15 and interfere with the proper seating of pins 16 and 17 within the pin holes.
The pins 16 and 17 are preferably constructed of fiberglass dowel of less than 9/16 thickness and 5 inch height. Those of skill in the art understand that other sizes and constructions would also be suitable, for example rebar steel or other suitable materials can be substituted for fiberglass. The pin holes 14 and 15 are placed relative to the placement of the receiving openings 12 and 13 so the block 1, when installed, functions together with its neighbors to provide a structurally sound, engineered retaining wall system.
In the preferred embodiment, the rearmost inner walls 18 and 19 of openings 12 and 13, respectfully, are spaced 1¼ inches forwardly of the forward most wall 11 of opening 10. By contrast, the pin holes 14 and 15 are positioned 1 inch forward of that same wall. Through this relative placement, each block 1 is secured in place on top of the blocks that form the lower course, leaving a ¼ of an inch setback for each successive course of blocks. The setback can be strategically greater or less depending on the appearance of the wall desired. This setback is shown in FIG. 4.
FIG. 4 also shows how the placement of the pin holes 14 and 15 relative to receiving openings 12 and 13 enhances the structural integrity by offsetting the pin holes 14 and 15 from the receiving openings 12 and 13. As best shown in FIG. 4, pin holes 14 and 15 are positioned such that no plane perpendicular to the front face 7 of block 1 ever runs through both pin hole 14 and receiving opening 12 or pin hole 15 and receiving opening 13. Such a plane could run through one or the other, but not both. As also shown in FIG. 4, the relative placement of the pin holes and the receiving openings in body 2 causes the legs 18 and 19 of neck 3 of each successive course of block 1 to be offset. Thus, just as the front face 7 of block 1 will not align with the face of the block above or below that block, neither leg 18 nor leg 19 of block 1 will not align with leg 20 of block 100 or leg 21 of block 200. This offset construction provides structural integrity without interfering with water drainage through opening 10.
The assembly of blocks to form a retaining wall is best described with reference to FIGS. 4 and 5. The lower course of a wall is formed by blocks 100 and 200. Those blocks are constructed the same way as block 1, described in connections with FIGS. 1-3, above. Locking pins 16 and 17 are shown in pin holes 14 and 15 of block 100 and block 200, respectively. Block 1 is shown on top of blocks 100 and 200 such that pin 16 in block 100 is engaged with the rearmost wall 18 of receiving opening 12 and pin 17 in block 200 is engaged with the rearmost wall 19 of receiving opening 13. FIG. 4 illustrates how block 1 is secured in place so as to create a minimum setback of approximately ¼ of an inch while ensuring leg 18 of block 1 does not align with leg 20 of block 100 below.
FIG. 5 shows a retaining wall 30 created by installing block 1 as described in connection with FIG. 4. As those of skill in the art will appreciate from this drawing, block 1 can be broken in half to finish wall 30.
FIG. 1 also shows ear portions 22 and 23 of head 4 and angled wall portions 24 and 25 of body 2. Ear portions 22 and 23 are formed during the manufacturing process to allow the blocks to be pushed off conveyor belts during the packing process without causing the blocks to roll over while being pushed. That is, the ear portions provide a layer surface to push on when the blocks are shoved off of conveyor belts during a packing operation.
During installation, ear portions 22 and 23 can be reduces in size or knocked off entirely to facilitate placement of a row of blocks 1 in a concave shaped retaining wall as shown in FIG. 6A. The ability of block 1 to be formed in a convex wall shape is also facilitated by the provision of angled side walls 24 and 25 on body 2. As an alternative, block 1 can be placed as shown in FIG. 6B to create a convex shaped retaining wall. In the case of a convex shaped retaining wall, the retention of ear portions 22 and 23 is immaterial. The size, shape and placement of receiving openings 12 and 13 relative to pin holes 14 and 15 facilitates the placement of block 1 in a concave or convex shaped pattern, while still providing for setback for each successive block course.
Irrespective of the size or shape of the wall constructed by serial placement of block 1, the depth and resultant stability of the wall is increased by including both neck 3 and head 4. In application, opening 10, and the spacing between legs 18 and 19 of adjacent block in the same row can be filled with gravel to further anchor the wall to the hillside while facilitating the drainage of water therethrough without harm to the integrity of the resulting retaining wall structure.
Various aspects of the different embodiments can be combined in different combinations to create new embodiments. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.