Patent Application
20060248832
This invention pertains to forms used for constructing concrete walls, and more particularly to wall form ties used for holding wall forms in a desired spaced-apart relationship defining a volume into which uncured concrete is poured and allowed to solidify.
Poured concrete walls are formed by pouring or pumping uncured concrete between rigid planar forms generally made of wood, aluminum, steel or a combination of these materials. Two series of coplanar forms are typically held in spaced-apart, parallel relationship by retaining ties to create a cavity in which the poured concrete wall is formed. Such ties typically comprise an elongated steel strip having circular apertures at opposing ends of the tie for passage of a pin that holds the tie between adjacent wall form panels. The conventional concrete wall form ties also include a plurality of notches configured for placement and retention of concrete reinforcing bars. These notches are typically defined on both of adjacent elongated edges of the bar so that the bar can be used in any of four different orientations, i.e., with either of the two ends of the wall form tie being attached to either of the two opposing wall forms, and with either elongate end facing upwardly. This eliminates the possibility of installing the wall form tie incorrectly in an upside down orientation.
This invention provides an improved, lighter weight concrete wall form tie having substantially the same strength characteristics of conventional concrete wall form ties. The reduced weight of the wall form ties of this invention allows the ties to be shipped at a significantly lower freight cost per unit. In addition, unnecessary material that does not add to the strength of the concrete wall form tie is removed and recovered as valuable scrap material that can be recycled to provide a lighter weight concrete wall form tie having strength characteristics comparable to conventional concrete wall form ties, while reducing both overall production costs and freight costs.
The concrete wall form tie of this invention comprises an elongated strip of material having two opposite elongate edges and a fastening aperture defined at each of two opposite ends of the elongate strip. A plurality of notches spaced-apart along each of the two opposite elongate edges of the strip of material between the fastening apertures are provided for proper placement and retention of reinforcing rods during pouring or pumping of concrete into a concrete wall form. Weight-reducing apertures are defined within an area between adjacent notches.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.
In
Each wall form includes vertical frame members 17, each defining a series of vertically spaced-apart apertures 18. Vertical frame members 17 also include a recess 20 adapted to receive an end 22 of wall tie 16. Typically, the depth of recess 20 is about equal to the thickness of wall tie 16 to allow adjacent vertical frame members 17 to abut each other with end 22 of wall tie 16 sandwiched between the abutting vertical frame members. A pin 24 passes through an opening (e.g., a circular aperture) 26 defined at each of opposite ends 22 of wall tie 16 to securely retain wall tie 16 within recess 20 and thereby hold the opposing walls in the desired spaced relationship defining a cavity into which concrete is poured.
As can be seen by reference to
Defined between adjacently spaced-apart notches 28 are tabs 32. Defined within the area of tabs 32 between notches 28 are apertures 34, which are cut or stamped out either during the initial stamping operation or during a subsequent supplemental stamping operation. Removal of excess material from tabs 32 to provide apertures 34 reduces the overall weight of wall ties 16 without compromising strength characteristics. In particular, it has been determined that failure of a wall tie 16 in accordance with the invention during tensile testing occurs at about the same level of strain as in an otherwise identical wall tie without apertures 34, and in each case failure occurs approximately along a line transverse to the length of the wall tie and approximately centered along the diameter of one of the fastening apertures 26. From this result, it has been reasonably concluded that cutting or stamping apertures 34 within the area of tabs 32 will not adversely affect strength characteristics of the wall tie 16, provided that the smallest total cross-sectional area of the elongate strip at a plane transverse to the length direction of the strip passing through the weight-reducing apertures 34 is greater than the smallest total cross-sectional area of the elongate strip at a plane transverse to the length direction of the strip passing through the center of either fastening aperture 26.
Wall tie 16 is typically fabricated from a strip of metal, such as steel or aluminum, having a substantially uniform thickness.
In addition to notches 28, typically having a semi-oblong shape, triangular notches 36 can be provided adjacent opposite end sections 22. Triangular notches 36 are not configured for holding or retaining reinforcing rods or bars, but instead are break-off notches that allow the end portions extending outwardly from each side of a completed concrete wall to be easily broken off.
The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.
