Static structures (e.g. – buildings) – Machine or implement
Reexamination Certificate
2000-02-08
2001-11-06
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Machine or implement
C052S301000, C052S678000, C249S033000, C072S101000
Reexamination Certificate
active
06311453
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the pouring of concrete and, more particularly, to a pin employed in the fixing of form boards between which the concrete is poured.
BACKGROUND OF THE INVENTION
As is known in the concrete pouring business, various types of pins are generally employed in the fixing of the form board. For the small, independent construction contractor who only occasionally does concrete work, a wooden pin is generally made—of 5/4 lumber and whittled to a point, for example—for driving into the ground in setting the board. While sometimes adequate to do the job, pins of this type are not often used (and, because it takes some time and labor to point the lumber, and because it is quite difficult to drive the pin the required depth into the ground to fix the form board, especially where there is an extensive amount of clay and shale present).
A concrete contractor working in the business, on the other hand, utilizes a pin made of steel, with holes drilled through at random intervals, to be driven into the ground next to the form board, and to receive nails hammered through the holes and into the board. While being made of steel—and therefore easier to drive into clay, shale, and other hard surfaces—, such pins are fairly expensive (e.g. priced at some $2.65 for a 16 in. pin of ¾ in. diameter, and with a 24 in. pin costing that much more). Experience has shown that it is not uncommon for a concrete contractor to purchase 200 or so pins of this type at any one time, packaged 10 to a box; and it then becomes quite annoying, as well as quite costly, to find such pins being lost, or rendered unusable when the holes begin to fill with overpoured concrete and allowed to set—each as a result of shoddy workmanship at the jobsite. Because dirt is continually being knocked about at the job location, because the steel form pins are of a color similar to that of the dirt, and because the colorization of the concrete is not that very much different from that of the pins, the construction worker frequently forgets to retrieve the pins after the nails have been pulled from the form board when the concrete has set. What with the chaos of the ongoing pour, it is not unusual for the worker to forget the pin, leaving it behind—or to forget to clean out the concrete which accumulates in the holes of the pin.
Experience has further shown that while the typical concrete construction worker does not view the retrieval of these form pins for later use as a priority item, such matter represents a major concern in the concrete pouring business, being one of an unnecessary recurring expense.
SUMMARY OF THE INVENTION
As will become clear from the following description, a new and improved form pin, according to the invention, continues to use a steel bar of given diameter and length—but one which does not include any holes drilled through at random intervals. A clip is employed, instead, having a first portion substantially in the shape of a cylinder and a second portion substantially in the shape of a tab extending at an angle from an outside surface of the cylindrical portion along its length. As will be described, the cylindrical portion of the clip is constructed of an inside diameter substantially equal to the given diameter of the steel bar, and with the tab portion having a plurality of spaced apertures extending through opposing planar surfaces of the tab. In accordance with the invention, furthermore, the clip is constructed of a deformable plastic to expand when then forced onto one end of the steel bar—with or without an opposing end of the steel bar being cut at an angle towards a point.
Experience has further shown that at the concrete construction jobsite there are almost always available unused concrete reinforcing rods termed “rebars”, of ⅜ in., ½ in., ⅝ in., and ¾ in. diameter of random lengths left over from an initial 20 ft. piece. Rather than throwing away these left-over pieces, the form pin of the invention utilizes the otherwise discarded rods, by cutting them to a 16 in., 24 in., or 32 in. length to serve as the steel bar of the form pin, being cut flush, substantially perpendicular to the length of the rebar at each end. As is known, such rebars incorporate a plurality of rims which circumscribe their outer surfaces.
According to the invention, the clip of the form pin is first selected of a color to contrast with that of the sand, shale or clay into which the steel bar is to be driven, and with the apertures of its tab portion being spaced, either as at the corners of a rectangle formed on the planar surfaces, or as spaced in the configuration of an X formed on such surfaces. To facilitate forcing the cylindrical portion of the clip onto the bar, both ends of the cylindrical portion are bevelled, a distance of the order of ⅛ in. To facilitate the removal of the form pin from the ground after the concrete has set, the tab portion of the clip extends outwardly from the cylindrical portion a distance to allow manual grasping by a user to twist the pin free. In a preferred embodiment of the invention, to be described, the cylindrical portion of the clip is selected of a length of substantially 3 in., while the tab extends outwardly a distance of substantially 1.5 in.
As will be described, the clip of the form pin is selected of a deformable plastic (such as polyethylene), for the cylindrical portion to be forced outwardly as the steel bar is hammered through the clip and into the ground. Such hammering serves to flatten the flush end of the bar in preventing the clip from loosening off the top—and when a rebar is employed, its circumscribing rims afford additional friction surfaces to hold the clip tight.
In another embodiment of the invention, the cylindrical portion of the clip will be seen to receive an O-ring, internal of the cylinder and of a deformable construction to groove under force of the rebar rims to further hold the clip secure and in place. When, for example, the clip is injection molded, the O-ring can be incorporated as part of the molding process, about ⅛ in. thick and positioned about ¼ in. in from either end of the cylindrical portion. Also, an additional flap can be included as part of the clip, internal of the cylindrical portion, and arranged to seat between adjacent ones of the rebar rims as the clip is hammered into position for use. Alternatively, a slot or hole can be cut into the cylindrical portion to accept a horseshoe clip or pressure pin to further hold the bar in place once inserted.
As will be appreciated by those skilled in the art, the clip of the invention becomes secure to the steel bar as the steel bar is hammered into the ground. With the clip fast in place, a cordless drill could then be employed to screw the combination to the form board, or it could be nailed instead. After the pouring process and the concrete sets, the screws are backed out—and the form pin removed by twisting and pulling upwardly on the tab portion or bar. Because of the contrasting colorization of the tab portion, the form pin will be readily identified and its retrieval can then follow easily.
REFERENCES:
patent: 1839286 (1932-01-01), Wolf
patent: 2831339 (1958-04-01), Jones
patent: 5301485 (1994-04-01), Shaw et al.
patent: 5568708 (1996-10-01), Kassardjian et al.
patent: 5670076 (1997-09-01), Leek
Reinforced Concrete, A Fundamental Approach, Third edition, Edward G. Nawy, 1996, Prentice Hall, 66.
Brodsky Charles I.
Friedman Carl D.
Varner Steve
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