Patent Application
20090235606
Concrete blocks, also referred to as concrete masonry units (CMU's), are typically manufactured by forming them into various shapes as part of an automated process employing a concrete block machine. Such machines typically employ a mold frame assembled so as to form a mold box, within which a mold cavity having a negative of a desired block shape is formed. To form a block, a pallet is moved by a conveyor system onto a pallet table, which is then moved upward until the pallet contacts and forms a bottom of the mold cavity.
The mold cavity is then filled with concrete and a head shoe assembly is positioned to form a top of the mold cavity. The head shoe assembly then compresses the concrete (typically via hydraulic or mechanical means) to a desired psi rating (pounds-per-square-inch) while simultaneously vibrating the mold cavity along with the vibrating table. As a result of the compression and vibration, the concrete reaches a level of “hardness” which enables the resulting finished block to be immediately removed from the mold cavity. To remove the finished block, the mold frame and mold cavity remain stationary while the shoe assembly, pallet, and pallet table move downward and force the finished block from the mold cavity. The conveyor system then moves the pallet bearing the finished block away and a clean pallet takes its place. This process is repeated for each block.
For many types of CMUs (e.g. pavers, patio blocks, light-weight blocks, cinder blocks, etc.), retaining wall blocks and architectural units in particular, it is desirable for at least one surface of the block to have a desired texture, such as a stone-like texture, for instance. When arranged to form a structure with the textured surface visible, the structure will have the appearance of being constructed from natural stone.
One technique for creating a desired texture on a block surface is to provide a negative of a desired texture or pattern on a moveable side wall of the mold cavity. During the manufacturing process, the side wall is moved to an extended position to form the mold cavity. As described above, the mold cavity is then filled with concrete and compressed/vibrated. The side wall is then moved to a retracted position and the finished block, as described above, is forced from the mold cavity and onto the pallet by the head shoe assembly. The finished block, including a surface having the desired texture, is then transported on the pallet by the conveyor for curing.
While such a technique is effective at forming a textured surface, air pockets trapped between the textured surface of the moveable side wall and concrete fill are forced out during the compression/vibration process, causing the concrete to settle proximate to the textured surface and resulting in the finished block having a height along the textured surface (e.g. front face of block) which is shorter than that along an opposite surface (e.g. rear face of block). Consequently, unless compensated for in some fashion, a structure (e.g. a retaining wall) will tend to have an undesirable lean in a direction toward the textured surface.
One embodiment provides a method of making a masonry block employing a mold assembly having a plurality liner plates each having a major surface that together form a mold cavity having an open top and an open bottom, wherein at least one liner plate is moveable between a retracted position and a desired extended position within the mold cavity. The method includes providing a negative of a desired texture on the major surface of the moveable liner plate, moving the moveable liner plate to a retracted position, closing the bottom of the mold cavity by positioning a pallet below the mold assembly, filling the mold cavity with dry cast concrete via the open top, vibrating the mold assembly and dry cast concrete therein, and moving the moveable liner plate to a desired extended position during the vibrating.
In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
In one embodiment, as illustrated, liner plate 40a is moveable between a retracted and a desired extended position within mold box 38, while liner plates 40b, 40c, and 40d are stationary. In other embodiments, up to all liner plates of the plurality of liner plates 40 are moveable between a corresponding extended and retracted position within mold box 38 to form mold cavity 42. In one embodiment, as illustrated, moveable liner plate 42a includes a liner face 44 having a negative of a desired texture, pattern, or other design to be formed on a face of a masonry block to be molded within mold cavity 42 by mold assembly 30.
Mold assembly 30 further includes a drive assembly 46 which is selectively coupled to and configured to drive moveable liner plate 40a and thus, moveable liner face 44, between the retracted and desired extended positions within mold cavity 42. In one embodiment, as will be described in greater detail below by
Mold assembly 30 is configured to selectively couple to a concrete block machine. For ease of illustration, the concrete block machine is not shown in
Drive assembly 46 further includes a master bar 66 having openings 68 and 70 through which support shafts 62 and 64 extend. In one embodiment, master bar 66 includes bushings 72 and 74 respectively mounted within openings 68 and 70. In one embodiment, bushings 72 and 74 comprise brass or other non-magnetic materials. Guide posts 76 and 78 are coupled between master bar 66 and moveable liner plate 40a and extend through corresponding openings 80 and 82 in side member 34a. A first drive element 84 having a plurality of angled channels 86 (illustrated by dashed lines) is coupled between master bar 66 and moveable liner plate 40a and extends through a corresponding opening 88 in side member 34a.
Drive assembly 46 further includes an actuator assembly 90. In one embodiment, as illustrated, actuator assembly 90 comprises a double-rod end hydraulic piston assembly including a dual-acting cylinder 92 and a hollow piston rod assembly 94 having a first hollow rod-end 96 and a second hollow rod-end 98. First and second hollow rod-ends 96 and 98 are stationary and extend through removable housing 60. Hydraulic fittings 100 and 102 respectively connect first and second hollow rod-ends 96 and 98 to a controller 104 via hydraulic fluid lines 106 and 108.
A second drive element 110 having a plurality of angled channels 112 configured to slideably interlock with the plurality of angled channels 86 of first drive element 84 is coupled to dual-acting cylinder 92. In one embodiment, the plurality of angled channels 112 are formed as part of a body of dual-acting cylinder 92 such that second drive element 110 is contiguous with the body of dual-acting cylinder 92. In one embodiment, as illustrated by
A drive assembly similar to drive assembly 46, including an actuator assembly employing gear elements and interlocking angled channels, similar to actuator assembly 90 and first and second drive elements 84 and 110, is described by U.S. patent application Ser. No. ______ assigned to the same assignee as the present invention, and which is incorporated herein by reference.
In one embodiment, drive assembly 46 further includes a magnetic sensor assembly 120 configured to provide a position signal 122 indicative of a position of moveable liner plate 40a to controller 104. In one embodiment, magnetic sensor assembly comprises a linear position sensor. Magnetic sensor assembly 120 includes a stationary magnetic sensor probe 124 which is mounted within a bored shaft internal to support shaft 62, and a permanent magnet 126 which is mounted to bushing 72 and which, as will be described below, is free to slide along support shaft 62 with master bar 66 when driven by double-rod end hydraulic piston assembly 90. The position of permanent magnet 126 relative to magnetic sensor probe 124 and, thus, a position of moveable liner plate 40a relative to mold cavity 42, is indicated by position signal 122. In one embodiment, magnetic sensor assembly 120 comprises a Model No. ______ linear position sensor as manufactured by ______.
In operation, with reference to
Because first drive element 84 is coupled to master bar 66, driving first drive element 84 toward desired extended position 132 also causes master bar 66 and guide posts 76 and 78 to move toward desired extended position 132. As master bar 66 moves toward mold cavity 42, permanent magnet 126 slides along support shaft 62 and, thus, along stationary magnetic sensor probe 124. As permanent magnet 126 moves along a length of stationary magnetic probe 124, magnetic sensor assembly 120 provides position signal 122 indicative of the position of permanent magnet along support shaft 62 and, thus, indicative of the position of moveable liner plate 40a relative to mold cavity 42. When position signal 122 indicates that moveable liner plate 40a has reached desired extended position 132, controller 104 stops transmitting hydraulic fluid to dual-acting cylinder 92 and maintains moveable liner plate 40a at desired extended position 132. It is noted that extended position 132 may vary for various type of masonry blocks formed by mold assembly 30.
Conversely, to move liner plate 40a away from mold cavity 42 toward retracted position 130, controller 104 transmits hydraulic fluid into dual-acting cylinder 92 via hydraulic line 108 and second hollow rod-end 9, causing dual-acting cylinder 92 and angled channels 112 of second drive element 110 to move along hollow piston rod 94 toward first hollow rod-end 96, and causing hydraulic fluid to be expelled from first hollow rod-end 96 via hydraulic line 106. As dual-acting cylinder 92 moves toward first hollow-rod end 96, the plurality of angled channels 112 of second drive element 110 interact with the plurality of angled channels 86 of drive element 84 and drive moveable liner plate 40a away from extended position 132 toward retracted position 130. In a fashion similar to that described above, when position signal 122 indicates that moveable liner plate 40a has reached retracted position 130, controller 104 stops transmitting hydraulic fluid to dual-acting cylinder 92 and maintains moveable liner plate 40a at retracted position 130.
In one embodiment, after mold cavity 42 is filled with concrete, head shoe assembly 50 is moved downward to mold cavity 42. The concrete block machine in which mold assembly 30 is installed (not shown) then begins to vibrate mold assembly 30 and head shoe assembly 50 begins to compress the concrete within mold cavity 42 as drive assembly 46 drives moveable liner plate 40a toward extended position 132. When position signal 122 indicates that moveable liner plate 40a has reached desired extend position 132, drive assembly 46 stops moving liner plate 40a and maintains it at extended position 132, and the vibration and compression continues as necessary.
By moving moveable liner plate 40a to extended position 42 after mold cavity 42 has been filled, and by compressing and vibrating the concrete within mold cavity 42 as moveable liner plate 40a is being moved toward extended position 132, air pockets trapped between the concrete within mold cavity 42 and textured liner face 44 are substantially removed during the block formation process.
With reference to
Retaining wall blocks, such as retaining wall block 140, are generally stacked in courses to form a structure, such as a retaining wall or planting bed, for example. Set-back flange 154 is adapted to abut against a rear face of a similar block in a course of blocks below retaining wall block 140 so as to position front face 142 at a desire set-back distance from the front face of the blocks in the course below.
At 204, one or more liner plates, such as moveable liner plate 40a, are positioned at a beginning or starting position. In one embodiment, the starting position comprises the corresponding retracted position of each moveable liner plate. In one embodiment, the starting position comprises a partially extended position. Depending on a particular implementation and a particular type of masonry block to be formed, mold assembly 30 may include one or more moveable liner plates. At 206, the concrete block machine positions pallet 52 so as to form a bottom for mold cavity 42.
At 208, the concrete block machine fills mold cavity 42 with a desired concrete mixture. At 210, after mold cavity 42 has been filled with concrete, head shoe assembly 50 is lowered onto mold cavity 42. At 212, the concrete block machine begins vibrate the concrete and to compress the concrete with head shoe assembly 50. Concurrently, controller 104 begins to move moveable liner plate 40a toward the desired extended position from the starting position (e.g. retracted position, partially extended position). When magnetic sensor assembly 120 indicates via position signal 122 that moveable liner plate 40a has reached the desired extended position, such as desired extended position 132, controller 104 stops moving moveable liner plate 40a and maintains it at the desired extended position. In one embodiment, after reaching the desired extended position, the concrete block continues to vibrate and compress the concrete fill within mold cavity 42 to achieve a desired psi rating.
At 214, after the concrete has been compressed and vibrated, the one or more moveable liner plates are moved to a retracted position. At 216, after the one or more liner plates have been moved to a corresponding retracted position, the concrete block machines removes the formed masonry block from mold cavity 42 by moving head shoe assembly 50 and pallet 52 downward while mold assembly 30 remains stationary. At 218, head shoe assembly 50 is raised to an original starting position, and the above described process is repeated for the formation of each subsequent block.
As described above and by previously incorporated U.S. patent application Ser. No. ______, drive assembly 46 employing first and second gear elements 84 and 110 provides a robust drive assembly that enables moveable liner plate 40a to be moved to a desired extended position while the concrete fill within mold cavity 42 is being compacted by head shoe assembly 50 and vibrated by the concrete block machine. Additionally, magnetic sensor assembly 120 provides accurate indication of the position of moveable liner plate 40a and is not as susceptible to vibration and other adverse conditions (e.g. dirt, debris) as other types of sensors (e.g. position switches, optical sensors). Other types of drive assemblies, however, may be employed, such as those drive assemblies described by U.S. patent application Ser. No. ______ assigned to the same assignee as the present invention, and which is incorporated herein by reference.
Additionally, although described herein primarily with respect to movement of a single liner plate and with respect to formation of a masonry retaining wall block, the teachings of the present invention apply to a mold assembly having multiple moveable liner plates and to the formation of other types of masonry blocks, such as architectural units, pavers, and cinder blocks, for example.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
This Non-Provisional patent application claims benefit of U.S. Provisional Application No. 61/038,144, filed Mar. 20, 2008, entitled: SYSTEM AND METHOD OF MAKING MASONRY BLOCKS, incorporated herein.
| Number | Date | Country | |
|---|---|---|---|
| 61038144 | Mar 2008 | US |
