Retaining wall cap unit
BACKGROUND AND SUMMARY 
     This invention relates to a concrete wall unit, and more particularly to a cap unit for a retaining wall. 
     In a retaining wall constructed of a plurality of courses of concrete blocks, it is known to form the uppermost course in the retaining wall of a series of cap units to cover the hollow cores of the blocks forming the lower retaining wall courses. 
     A particularly advantageous block structure for constructing a retaining wall is disclosed in my co-pending application Ser. No. 07/304,793 filed Jan. 31, 1989. The retaining wall block therein disclosed includes a rear web having a recess formed in its upper surface, with a clip adapted for placement therewithin. The clip has depending inner and outer legs for engaging the inner and outer surfaces of the rear web, and an upper portion therebetween which is adapted for placement within the recess. An upstanding portion of the clip projects upwardly above the upper surface of the block to which the clip is mounted, for engaging the inner surface of the rear web of a block in the course thereabove. 
     The present invention provides a cap unit block structure for use on a retaining wall constructed of a plurality of courses of blocks as described. A plurality of cap units according to the invention are adapted for side-by-side placement atop the uppermost course of retaining wall units to form the topmost block course and to cap off the retaining wall so constructed. In accordance with the invention, a retaining wall cap unit comprises a cast concrete block having an upper surface, a lower surface, first and second end surfaces and first and second side surfaces. The upper surface of the cap unit is substantially solid so as to provide a cavity-free cap to the retaining wall. A cavity is formed in the bottom surface of the unit, and is adapted to receive the upstanding portion of the clip mounted to a block in the course therebelow. In a preferred embodiment, the cavity preferably comprises a slot extending throughout substantially the entire width of the cap unit bottom surface between the first and second side surfaces. The cap unit is constructed so that one of the first and second end surfaces is narrower in width than the other of such surfaces. To provide this structure, one of the side surfaces is disposed so as to be substantially perpendicular to both the first and the second end surfaces, while the other of the side surfaces is disposed in a non-parallel relationship to the first-mentioned side surface. With this construction, a straight run is provided by alternately placing the cap units so that one cap unit has its narrow end surface facing outwardly while the adjacent cap unit has its wide end surface facing outwardly. To form an inside radius of curvature, the cap units are placed so that adjacent cap units all have their narrow end surface facing outwardly. Conversely, to form an outside radius of curvature, the cap units are placed so that adjacent cap units all have their wide end surfaces facing outwardly. To accommodate the alternating placement of the cap units to provide a straight run as well as inside and outside curvatures, a pair of cavities as discussed previously are provided on the bottom surface of the cap unit. The cavities are disposed on the bottom surface of the cap unit such that one cavity is located adjacent one of the end surfaces and the other cavity located adjacent the other of the end surfaces. In this manner, no matter which way the cap unit is oriented on the block in the course therebelow, a cavity is provided for receiving the upstanding portion of the clip which is mounted to the lower block. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate the best mode presently contemplated of carrying out the invention. 
     In the drawings: 
     FIG. 1 is an isometric view of a cap unit constructed according to the invention; 
     FIG. 2 is a side elevation view, partially in section, showing a cap unit constructed according to the invention as positioned on a block forming a part of a course below the cap unit course, with a portion broken away; 
     FIG. 3 is a plan view of a cap unit constructed according to the invention; and 
     FIG. 4 is a plan view of a plurality of cap units of the invention forming a straight wall portion, an inside radius of curvature and an outside radius of curvature. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIG. 1, a retaining wall cap unit 10 includes an upper surface 12, a lower surface 14, first and second side surfaces 16, 18, respectively and first and second end surfaces 20, 22, respectively. As can be seen more clearly in FIG. 3, first and second end surfaces 20, 22 are substantially parallel, and end surface 20 has a width less than that of end surface 22. First side surface 16 extends between end surfaces 20, 22 and is substantially perpendicular to end surfaces 20, 22. Second side surface 18 extends between first and second end surfaces 20, 22, and is disposed in a non-parallel relationship to first side surface 16. 
     With reference to FIG. 2, cap unit 10 is adapted for placement on the upper surface of the topmost course of retaining wall blocks, one of which is shown at 24. Cap unit 10 is adapted for placement on block 24 such that bottom surface 14 is disposed adjacent the upper surface of block 24, with upper surface 12 facing upwardly Upper surface 12 is substantially solid in construction, providing a cavity-free cap to a retaining wall formed of a plurality of blocks such as 24, which typically have one or more cavities formed therein. 
     Generally speaking, cap unit 10 is substantially narrower in width than the width of the retaining wall blocks therebelow, such as 24. 
     With further reference to FIG. 2, retaining wall block 24 has a connector member in the form of a clip, shown generally at 26, mounted to its rear web, shown at 28. Clip 26 includes an inner leg 30 and an outer leg 32, between which an upper portion 34 extends. As explained in my co-pending application Ser. No. 07/304,793, upper portion 34 is disposed within a recess 36 formed in the upper surface of rear web 28. Clip 26 further includes an upstanding portion 38 which projects upwardly from the upper surface of block 24, and which may be provided with a rearwardly extending lip 40. 
     The underside of cap unit 10 includes a pair of cavities 42, 44, which open onto cap unit bottom surface 14. Cavities 42, 44 are preferably constructed in the form of slots extending between side surfaces 16, 18 and opening thereonto, so as to extend the entire width of cap unit 10. As shown, slot 42 is disposed adjacent cap unit end surface 20, and slot 44 is disposed adjacent end surface 22. Slots 42, 44 extend upwardly within cap unit 10 less than the full height thereof. 
     Referring still to FIG. 2, slot 42 is adapted to receive upstanding portion 38 of clip 26 mounted to block 24. Slot 42 includes a recess 46 which is adapted to receive lip 40 of clip upstanding portion 38. After lower block 24 is installed and clip 26 mounted thereto, cap unit 10 is simply positioned thereover so that clip upstanding portion 38 is received within slot 42, whereafter cap unit 10 is moved forwardly (rightwardly, with reference to FIG. 2), so that lip 40 is received within recess 46 and upstanding portion 38 engages the rear wall of slot 42. In this manner, upstanding portion 38 prevents lateral forward movement of cap unit 10, and lip 40 prevents inadvertent uplifting of cap unit 10. 
     As shown, cap unit 10 has a depth greater than that of block 24 so that second end surface 22 overhangs the front surface of block 24. In this manner, entry of moisture into the cavities of block 24 is prevented. 
     Referring now to FIG. 4, a plurality of cap units 10 are illustrated forming the uppermost course in a retaining wall. To form a straight section, shown at the leftward end of FIG. 4, cap units 10 are positioned such that first and second end surfaces 20, 22 alternately face outwardly. To form an inside radius of curvature, cap units 10 are positioned such that only first end surfaces 20 face outwardly. The narrower dimension of first end surface 20 relative to second end surface 22, with placement of side surfaces 16, 18 adjacent each other, provides the inside radius of curvature. Conversely, to provide an outside radius of curvature, cap units 10 are positioned so that only second end surfaces 22 face outwardly. The cap unit course can thus be constructed so as to conform to the shape of the wall provided by the lower retaining wall blocks. 
     In order to accommodate the alternate placement of cap units 10 as described with reference to FIG. 4, one or the other of slots 42, 44 receives the upstanding portion, such as 38, of the clip mounted to the block, such as 24, in the course therebelow. Clips 26 are selectively placed within the block cavities so that each cap unit receives the upstanding portion of a clip to retain the cap unit on the wall. 
     Various alternatives and modifications are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.