Static molds – Mold element – In situ construction engineering or building type
Reexamination Certificate
2001-07-31
2004-03-09
Yip, Winnie S. (Department: 3637)
Static molds
Mold element
In situ construction engineering or building type
C249S219100, C052S127300, C052S742140, C052S699000
Reexamination Certificate
active
06702247
ABSTRACT:
BACKGROUND OF THE INVENTION
Tilt-up (or precast) construction of concrete wall sections is well-known in the art. In such an approach, forms are placed edgewise on a flat casting surface, and filled with concrete, which is then cured. Once the concrete has set, the form is removed and the wall is tilted up into the preferred, typically vertical, orientation. Most forms are made of conventional wood planks, such as two-by-eights and the like. To keep the wood from shifting during the form assembly portion of the operation, as well as to provide smooth, beveled edges to the finished concrete slab, single or double chamfers have been employed. These chamfers are often in the shape of a triangle with an extended base for plank edge support (in the case of the single chamfer variant), or a trapezoidal member with a plank-engaging channel disposed in the center (the dual chamfer variant). When placed in the chamfer, the vertically extending widthwise dimension of the plank defines the thickness of the concrete wall panel to be poured. The chamfer is placed to engage every plank that makes up the form.
One problem associated with conventional chamfer construction is the tendency of the poured concrete to leak into gaps prior to drying and hardening. This problem is especially acute between the chamfer and the casting surface, and between the chamfer and the plank, as the resulting dried portion that has leaked through can stick to the chamfer, which can in turn lead to an unintended, cost-prohibitive one-time chamfer use. In addition, if the dried concrete that has leaked through bonds to the finished product wall section and subsequently breaks off during handling, the bond might be strong enough to take portions of the finished product with it, thus adversely effecting the quality of the finished product. Prior art attempts at providing a seal to preclude the occurrence of leaking have been of a passive nature in that the chamfer relies on a close fit to accept a plank of standard thickness without gaps, but does nothing to actively close plank-to-chamfer gaps. In addition, no attempts have been made to provide seals between the chamfer and the casting surface.
Accordingly, there exists a need for a device that can ensure that tilt-up wall panels are precast with a minimum amount of poured concrete bleed-through, thereby avoiding frame-chamfer bonding and subsequent difficulty in separating the two.
SUMMARY OF THE INVENTION
The need is met by the present invention, which comprises a sealing chamfer used to support tilt-up wall panels without the disadvantages of the prior art. According to a first aspect of the present invention, a chamfer for engaging a plank to form concrete wall panels for tilt-up construction is disclosed. The chamfer, which includes a base portion, at least one chamfer portion, and a plank-accepting portion defined by adjacent cooperation of the base and chamfer portions, is configured for substantially horizontal placement upon a casting surface, such as a smooth floor. As such, it can accept a form, preferably made of individual wood planks secured together, which can be coupled to the chamfer to produce a mold capable of accepting poured concrete. The base portion defines a base plane, and is elongate along a lengthwise direction and terminates in a pair of lateral edges that project along a widthwise direction. Both the upper and lower surfaces of the base portion are substantially flat. Each chamfer portion is disposed along one of the pair of lateral edges of the base portion and is substantially coextensive therewith along the base portion's lengthwise direction. Each chamfer portion defines a generally triangular shaped structure (when viewed end-on) made up of a normal leg disposed normal to the base portion to define a normal leg plane and an angular leg angularly disposed relative the normal leg. The angular leg additionally defines at least one flexible edge that projects beyond at least one of the base plane or the normal leg plane. As a result, when the chamfer includes a flexible edge that projects beyond the base plane, and is placed on a substantially flat casting surface, the substantially flat lower surface of the chamfer's base portion does not contact the casting surface. The gap formed by this configuration permits a certain amount of flexure in the chamfer when a load is applied. This flexure allows these cantilevered flexible edges of the chamfer portion to move in response to the base portion such that when the base portion flexes under a load (such as the placement of a plank in the plank-accepting portion), the fit between the flexible edges and an abutting surface, such as a plank or casting surface, is enhanced, thereby minimizing or eliminating the leakage of the poured concrete to areas outside the preconfigured mold volume. As used in conjunction with the present disclosure, the term “substantially” refers to an arrangement of elements or features that, while in theory would be expected to exhibit exact correspondence or behavior, may, in practice embody something slightly less than exact. For example, in the present context, even if the chamfer portion is cut short near the ends of the chamfer to facilitate the right-angled joining of two or more chamfers, the extension of the chamfer portion is still “substantially coextensive” with the elongate base portion under the present definition. By way of another example, a portion need not project perpendicularly out of a horizontal plane to be considered “substantially upstanding” as long as it points in a generally upward direction.
Optionally, a pair of flexible edges can be configured to extend from each angular leg such that one of the flexible edges projects beyond the base plane, while the other projects beyond the normal leg plane. An additional option includes having the one or more flexible edges be cooperative with the base portion such that, upon application of a load to the base portion, the base portion flexes to effect a sealed relationship between the one or more flexible edges and the casting surface, plank or both. The one or more chamfer portions may further comprise a cantilever leg that extends angularly from the angular leg and is disposed coplanar with the base portion. Moreover, the chamfer can be made of plastic, such as polyvinyl chloride (PVC). The use of such materials is beneficial in that, in addition to being inexpensive to produce (such as by extrusion, where long, continuous pieces can be made and cut to desired lengths), they are fracture-resistant as well as relatively non-stick, so that what little dried concrete residue remains after each use can be easily removed, thus prolonging the useful life of the chamfer. By virtue of the continuous-production nature of PVC and related materials, the chamfer and base portions can optionally comprise one piece, thus obviating separate joining steps.
According to another aspect of the invention, a chamfer includes a base portion and a pair of chamfer portions disposed along the base portion's widthwise lateral edges. The dual chamfer configuration is similar to that of the previous embodiment, with the exception that both widthwise edges of the base portion have a chamfer portion disposed along them. Accordingly, the plank-accepting portion is now defined by a channel, formed on the bottom by the base portion, and on the sides by the opposed upstanding normal legs of the chamfer portion pair. As before, the chamfer portion extends substantially the entire length of the base portion's elongate dimension. The lower surface of the base portion is configured to not engage with the casting surface until an application of a load on the chamfer. As with the previous embodiment, in one option, the at least one flexible edge can be a pair of flexible edges configured to extend from each angular leg such that one of the flexible edges projects beyond the base plane, while the other projects beyond the normal leg plane. An additional option includes having the one or more flexible edges be cooperati
Dinsmore & Shohl LLP
Fukuvi USA, Inc.
Yip Winnie S.
LandOfFree
Tilt-up construction chamfers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tilt-up construction chamfers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tilt-up construction chamfers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3217680