Road structure – process – or apparatus – Apparatus – Means to install or form joint
Reexamination Certificate
1999-10-01
2001-01-23
Bagnell, David (Department: 3673)
Road structure, process, or apparatus
Apparatus
Means to install or form joint
C404S087000, C404S100000
Reexamination Certificate
active
06176643
ABSTRACT:
This invention relates to so-called slipform pavers having dowel bar inserters. Specifically, a detachable dowel bar inserter kit is disclosed which finds special application to portable slipform pavers.
BACKGROUND OF THE INVENTION
Concrete slipform pavers are known. Specifically, such pavers include a “tractor” and a “paving kit”.
Regarding the tractor, most concrete slipform pavers include a tractor, which is comprised of a rectilinear frame. This rectilinear frame has bolsters extending parallel to the direction of machine travel and cross beams extending across the paved roadway. The rectilinear frame thus straddles the concrete roadway or runway while it is paved. This frame is propelled and supported on either end by side crawler track(s). The frame supports a diesel engine driven hydraulic power unit, which supplies power to the tractor and paving kit.
The paving kit is typically suspended below the rectilinear tractor frame by mechanical means. The paving kit takes its hydraulic power from the power unit on the tractor. The tractor and paving kit comprise the slipform. This slipform passes over concrete placed in its path. The concrete is placed in a relatively even and level mass that can be conveniently paved. During this slipform process the tractor attached paving kit spreads the concrete dumped in the path of the paver, levels and vibrates it into a semi-liquid state, then confines and finishes the concrete into a slab with an upwardly exposed and finished surface. Sideforms mounted to the side of the slipform kit confine the sides of the slab during the paving process.
The tractor typically has either two or four crawler tracks supporting and propelling the frame and attached paving kit. Other kits can be attached to these tractors such as kits for conveying and spreading concrete and trimming and spreading base materials. For the purposes of this description, we will focus on the paving kit working in conjunction with a rear mounted, dowel bar inserter kit used for slipforming a concrete slab and concurrently inserting dowel bars in the plastic concrete across the slipform slab.
Dowel bar and tie bar inserters for such paving machines are known. Dowel bars are placed parallel to the direction of machine travel and ties bars are placed across the direction of machine travel. Specifically, three types of inserters for such bars are known. First, there is the tie bar inserter for the edge of the slab. This tie bar is placed transverse to the paving direction and enables tying of sequentially placed side-by-side slabs, one to another. This type of tie bar and tie bar inserter is not of concern here.
Second, there is the tie bar inserter for placing tie bars completely within the placed slab. A placed slab might be a two or more 12′ (3.657 mm) wide lane being placed concurrently in one pass. These tie bars are placed in a line transverse to the direction of machine travel. These tie bars enable a joint to be subsequently cut in the middle of the slab parallel to the direction of machine travel. Expansion of the slab across the dimension of machine travel is permitted. This type of tie bar and dowel bar inserter is not of concern here.
Finally, and the most difficult insertion problem is the dowel bar inserter for placing dowel bars parallel to the direction of machine travel. The dowel bars are simultaneously placed in a line (or row) on what are typically 12″ (305 mm) centers, across the entire slab being slipformed by the paver. These dowel bars enable a joint to be subsequently cut in the slab across the direction of machine travel. The dowels provide load transfer between the adjoining panels in the direction of machine travel.
This type of dowel bar inserter presents the most difficult insertion problem in any slipform paver. Additionally, this type of dowel bar inserter requires modification to be made to the slipform paver to attach the dowel bar inserter. In addition to this, great effort is required to attach or remove the dowel bar inserter from the slipform paver. It might take an additional two days to assemble a machine with a dowel bar inserter. This great effort has limited the dowel bar inserter's acceptance on smaller paving jobs. In what follows, we first discuss the most modern pavers, which have been developed. Second, we turn to the prior art problem of dowel bar insertion. Third, we set forth the mechanical problem of attachment and removal of dowel bar inserters to known pavers, including the pavers summarized above.
In Guntert et al U.S. Pat. No. 5,590,977 issued Jan. 7, 1997 entitled Four Track Paving Machine and Process of Transport we have disclosed a portable slipform paver that used telescoping members in the direction of machine travel. A four track paver is disclosed having a frame which telescopes for transport to reduce the dimension of the machine in the direction of paving machine travel. A rectilinear tractor frame is provided. The frame includes four crawler tracks, one connected to each corner of the frame via a side bolster. The crawler tracks are directly supported on a hydraulic cylinder and mounted for pivotal movement about the vertical axis of the hydraulic cylinder. The frame telescopes at side bolsters between the leading and trailing crawler tracks at the sides of the machine. When expanded, the paving machine has the full dimension required for paving. When contracted, the paving machine has a profile allowing convenient transport. Most importantly, such expansion and contraction of the machine in the direction of paving travel does not require substantial paver or paver kit disassembly. As a consequence, a convenient method of loading and off loading to a hauling flatbed trailer exists. With the frame contracted at the side bolsters and the tracks pivoted parallel to the pavement spanning dimension of the frame, both frame and paving kit are elevated and a transporting flatbed trailer moved under the paver. Supports are installed to relieve the slip form paving kit from the full weight of the tractor frame, and the tracks lifted. There results a four track paver profile transportable within a maximum width envelope which can be legally transported on the highway without a pilot car (in the U.S.A. this is this is 12′ or 3.657 M.) This patent is incorporated by reference to this disclosure as if set forth in full.
In Guntert et al U.S. Pat. No. 5,615,972 issued Apr. 1, 1997 entitled Paving Machine with Extended Telescoping Members (see also U.S. Pat. No. 5,647,688) we have disclosed a portable slipform paver having an extendable width. A conventional telescoping frame on a paving tractor is provided with fixed frame cross beam extension members for insertion to and attachment with a telescoping frame member. The conventional telescoping frame includes paired forward and paired rear side-by-side female tube members. Each forward and rear tube member conventionally acts for the telescoping support of male extension members which attach directly to the side bolster, which in turn attaches to the hydraulic jacking columns and crawlers. Within the limits of expansion, the male extension members co-acting with clamps acting through the female tube members provide for both movement of the point of crawler support and expansion of the paving width of the tractor frame. Into this combination, extenders are added for attachment to the supported end of the male extension members interior of the female telescoping members. During frame width expansion, the male telescoping members are expanded to register their ends interior of the female telescoping members to attachment access ports in the female telescoping member. The extenders are inserted, supported, and registered at complimentary attachment apertures with attachment to the male telescoping members taking place. Once attachment has occurred, further extension of the male telescoping members occurs. A simple system of pinned cross bracing reinforces the extended frame with relatively light bracing members. When the telescoping members at both sides of t
Dahlinger Gerald Lee
Francis Richard W.
Guntert, Jr. Ronald M.
Bagnell David
Guntert & Zimmerman Const. Div.
Pechhold Alexandra K.
Townsend and Townsend / and Crew LLP
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