Patent Application
20090178365
This method relates to meter pits; and more particularly relates to a novel and improved method of fabricating a precast concrete meter pit.
Meter pits for water meters are customarily fabricated out of plastic or stacked concrete in the form of a cylindrical pipe. The plastic meter pits typically sell at a higher price than concrete pits and tend to deform under certain conditions. The concrete-sectioned meter pits are assembled in segments using a tongue-and-groove connection which is labor intensive and also poses a safety risk when assembling the meter pits by hand which must be transported and assembled on site. The pipes are then buried in the ground, typically below frost level, and have an upper end which is adapted to receive a cover in order to withstand extremely cold temperatures and particularly to insulate the water meter from cold temperatures. However, there is a need for a method of fabricating a meter pit which can be made of one-piece construction in a one-step slip form operation and which will afford the necessary support ledge for a cover.
In addition, packerhead assemblies have been devised for slip forming concrete pipe including a trowel assembly at one end of the packerhead assembly to form an outwardly directed, offset end but for several reasons are not practical for use as a meter pit. A representative patent is U.S. Letters Patent No. 5,080,571 to Crawford incorporated by reference herein in which a trowel assembly is employed in association with the packerhead assembly to specially shape one end of the concrete pipe. Accordingly, there is a need for a novel and improved method for fabricating meter pits of one-piece construction with an upper edge which is capable of accommodating a cover.
Other representative patents in the field of concrete pipe making are U.S. Pat. Nos. 2,751,657 to Holston, 3,632,270 to Baker, 3,724,506 to Crowe, 3,922,133 to Crawford et al, 4,118,165 to Christian, 4,248,580 to Christian, 4,253,814 to Christian, 4,540,539 to Crawford et al, 4,690,631 to Haddy, 5,080,571 to Crawford, 5,215,604 to Crawford, 5,248,248 to Adly, 5,364,578 to Grau, 5,456,590 to Volmari, 5,616,351 to Wensauer and 5,648,108 to Hvidegaard.
It is therefore desirable to provide for a novel and improved method for making a meter pit.
It is also desirable to provide for a novel and improved meter pit which can be fabricated out of concrete in a one-step slip forming operation.
It is also desirable to provide for a novel and improved apparatus for manufacturing precast concrete meter pits in a simple and efficient manner.
It is still further desirable to provide for a precast concrete meter pit having a thickened support ledge at one end which is capable of supporting the standard cover for meter pits.
Accordingly, a method of fabricating a meter pit, the meter pit comprising an elongated precast concrete pipe of generally cylindrical configuration having a ledge projecting radially inwardly from one end thereof and wherein the pit is made from the steps of positioning a pallet having a concentric jacket attached thereto on a turntable, lowering a packerhead assembly within the jacket, the packerhead having a concentric rollerhead provided with a trowel, the trowel having a radially inwardly and downwardly inclined lower edge which forms an inner surface of the support ledge, injecting concrete into an annular space between the jacket and rollerhead for downward flow until the space is entirely filled, and raising the rollerhead and trowel as the annular space is being filled.
The preferred apparatus is of the type for making a precast concrete meter pipe characterized by a packerhead assembly including a longbottom assembly and a rollerhead assembly, a jacket in outer spaced concentric relation to the packerhead assembly, and means for rotating the packerhead assembly and characterized by the longbottom assembly including a trowel being of generally cylindrical configuration and terminating in a radially inwardly and downwardly inclined lower edge, and an annular pallet positioned beneath the trowel having a riser circumscribing an inner annular edge thereof and extending upwardly within the trowel. In practice, the pallet is vibrated as the concrete is advanced by gravity flow through the space between the jacket and packerhead assembly to rapidly fill and pack the entire space beginning with the enlarged area between the lower end of the trowel and jacket.
The above and other objects, advantages and features will become more readily appreciated and understood from a consideration of the following detailed description of preferred and modified forms when taken together with the accompanying drawings in which:
There is illustrated in
The terminal end 14 of the beveled edge 13 is substantially flat and squared to the longitudinal axis of the pipe so as to form a ledge or seat for supporting a generally bell-shaped cover 16. The cover 16 is of standard construction including spaced projections or posts 18 which fit inside the ledge 13 and help to position and situate the cover 16 on the support ledge 13. The cover 16 is commonly referred to as a double lid cover which provides a dead air space between the top lid and the interior of the pit 10. The dead air space acts as an insulator, retaining pit heat and keeping outside cold air from entering. The meter pit as described is equally conformable for use with single lid covers and flat covers which may be utilized in milder climates. Grade rings (not shown) may also be inserted between the cover 16 and the support ledge 13 to adjust the height of the cover 16 to match the surface grade.
A preferred form of apparatus 20 for manufacturing meter pits 10 is illustrated in
A packerhead assembly 39 includes a rollerhead assembly 38 which is mounted for rotation on a packer shaft 40 and a longbottom assembly 42 which is comprised of a mounting flange (not shown) and the trowel or trowel assembly 44. The jacket 22 is in outer spaced concentric relation to the rollerhead and trowel assemblies. The rollerhead assembly 38 is of standard construction and, for example, is disclosed in hereinbefore referred to U.S. Pat. No. 5,080,571, incorporated by reference herein. However, the longbottom assembly 42 which is positioned directly beneath the rollerhead assembly and joined for rotation therewith includes the trowel 44 which inclines somewhat diagonally and inwardly in a downward direction with a lower edge 46 bearing lightly against a riser portion 48 of the pallet 34. The pallet 34 is annular and positioned beneath the trowel assembly 44, an inner annular edge 49 of the riser 48 extending upwardly within the trowel assembly 44. The pallet 34 is also provided with radially inwardly projecting teeth 50 at spaced intervals around the inner surface of the riser 48, and downwardly projecting flanges 52 which serve to aid in rotation and vibration of the pallet and also serve to act as stabilizers when the pallet 34 is placed on an uneven surface. A top centering plate or cover plate 55 is bolted to a top table 55 and is positioned on the jacket 22 with centering blades 26′ and has downwardly projecting lobes 56 at spaced circumferential intervals to form the notches 15 for insertion of the water lines as described.
In the standard pipe making process as employed in the hereinbefore referred to U.S. Pat. No. 5,080,571, concrete is injected into the space between the jacket and rollerhead wherein the longbottom assembly and rollerhead assembly are rotated in opposite directions as they are advanced upwardly so as to compact the concrete with centrifugal force and packing pressure from the rollerheads in accordance with standard pipe making procedures. Also, when used in association with the pallet in pipe making processes, the pallet is caused to spin and to vibrate. In the present form, however, the pallet typically only vibrates but is capable of spinning.
Accordingly, the meter pit 10 is fabricated upside down by the apparatus 20. Specifically, the pallet 34 permits the longbottom assembly and more specifically the trowel 44 to extend around the outer circumference of the pallet in forming the support ledge 13 with an inner beveled surface portion 14′. For this purpose, the pallet 34 has the beveled edge 49 on the riser 48 to assist in centering and sliding the trowel assembly around the outer edge of the pallet. However, the pallet does not spin as typically required for pipe making but instead is journaled with respect to the table and caused to vibrate in a manner to be described. It is important to note that while this manufactured meter pit does not typically require rotation of the pallet 34, further compaction of the cement may be achieved with rotation as well as vibration of the pallet 34.
Summarizing the steps followed in the meter pit fabrication procedure:
Basically no further finishing steps are required before the meter pit is installed in the ground in a right-side-up position with the support ledge 13 at the upper end and with the notches 15 being at the lower end and straddling the water lines.
It is therefore to be understood that while preferred forms are herein set forth and described, the above and other modifications may be made therein without departing from the spirit and scope as defined by the appended claims and reasonable equivalents thereof.
This application is a Continuation of U.S. Ser. No. 11/048,544, filed 31 Jan. 2005, entitled “PRECAST CONCRETE METER PIT AND METHOD AND APPARATUS FOR MAKING SAME,” which application is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11048544 | Jan 2005 | US |
| Child | 12408502 | US |
