Patent Application
20100084533
The present disclosure relates generally to the bracing of a concrete column form for ensuring that the form remains plumb while the concrete is poured and during curing of the concrete. The present disclosure relates more particularly to a bracing attachment device adapted to be secured about a column form, the device providing attachment sites to which braces can be attached.
Conventionally, a concrete column form is encircled at its top end by a square frame constructed from 2×4 boards or the like. The frame is affixed to the form in suitable fashion, and a pair of long braces (typically also made from 2×4s) are nailed to the frame and extend down to engage the ground. The process for bracing a column form in this manner is relatively cumbersome.
In Europe, a flexible strap with an attachment fitting has been used for encircling the upper end of a concrete form. The fitting has a threaded bolt and nut. In one technique, a hole is drilled through the end of a 2×4 brace and the threaded bolt is inserted through the hole and the nut is engaged with the bolt to secure the brace to the fitting. In another technique, a nail plate is nailed to the end of the brace and defines a hole for receiving the bolt of the attachment fitting, the nut then securing the nail plate to the fitting.
It is not uncommon for a worker perched on a ladder at the top end of the concrete form to drop the nut while trying to thread it onto the bolt. Not only is this a potential hazard for people below, but it is also an annoyance for the worker, who must then descend the ladder to retrieve the nut, thus wasting time.
In accordance with embodiments disclosed herein, a toggle device is provided for attachment to a form-engaging assembly securable about the upper end of a concrete form. The toggle device is configured to attach to a brace either directly or via a nail plate attached to the end of the brace. The toggle device does not have any nut or other part that must be removed and then replaced in order to secure the brace to the fitting. Instead, the toggle device can toggle between two different configurations. One configuration is suitable for attachment directly to a brace, and the other configuration is suitable for attachment to a nail plate on a brace.
In one embodiment, the toggle device comprises a base plate to which an elongate first member is rigidly affixed so that it projects from the base plate. An elongate second member is connected to the first member by a sliding pivot connection. The sliding pivot connection is such that the second member can be moved from one position in which it is parallel to and overlapping with the first member, to another position in which it is generally perpendicular to the first member, to yet another position in which it is oblique to the first member. In one embodiment, the second member can rotate a full 360 degrees about the pivot connection.
To connect the toggle device to a 2×4 brace, the second member is placed in the parallel overlapping position and the first and second members are inserted through a hole in the brace. The second member is extended via the sliding connection until it fully emerges from the hole on the opposite side of the brace from the base plate, and then the second member is pivoted into a position preventing the toggle device from being withdrawn through the hole, thus capturing the brace. In one embodiment the second member is positioned substantially perpendicular to the first member to capture the brace.
To connect the toggle device to a nail plate on a brace, the second member is placed in the parallel overlapping position and the members are inserted through a hole in the nail plate. The second member is then pivoted into a position preventing the toggle device from being withdrawn through the hole in the nail plate, thus capturing the nail plate. In one embodiment the second member is positioned obliquely to the first member to capture the nail plate.
In one embodiment, the form-engaging assembly comprises a flexible strap. The base plate of the first toggle device can include a pair of slots spaced apart along a length of the base plate, the strap being passed through the slots to secure the first toggle device to the strap.
In order to secure two braces to the column form, a second toggle device substantially identical to the first toggle device can be secured to the strap, the first and second toggle devices being spaced apart along a length of the strap. In one embodiment, the toggle devices can be slid to various positions along the strap for adjusting the toggle devices to accommodate column forms of different circumferences.
The strap can include a pair of cooperative connecting devices affixed to the strap, the connecting devices being configured to connect to each other to form the strap into a loop about the column form. The strap can also include a tensioning device operable to constrict the loop about the column form.
In one embodiment, one of the first and second members of the first toggle device has a slot that is elongated along the longitudinal axis of the member, and the other of the first and second members supports a pivot pin engaged in the slot such that the pivot pin can slide along the slot. In a particular embodiment, the slot is defined in the second member and the pivot pin is affixed to the first member. The first member can be generally U-shaped having a pair of spaced legs, and the pivot pin can be connected between the legs. In this embodiment, the second member is received between the legs.
In one embodiment, the first toggle device is configured such that when the second member is in the perpendicular position a minimum distance between opposing surfaces of the base plate and second member is adequate for accommodating a thickness of a 2×4 or 4×4 board therebetween. A 2×4 board typically has a thickness of about 1.5 inches, while a 4×4 board is about 3.5 inches thick, and hence the minimum distance is about 1.5 inches to about 3.5 inches. When the second member is in the oblique position a minimum distance between opposing surfaces of the base plate and second member is adequate for accommodating a thickness of a 1/16-inch thick plate therebetween. In all embodiments, the minimum distance in the oblique position is substantially smaller than the minimum distance in the perpendicular position.
The sliding pivot connection is structured and arranged such that when the second member is in either the perpendicular position or the oblique position, the second member is substantially prevented from moving away from the base plate to increase the minimum distances.
Having thus described the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The present invention now will be described more fully hereinafter with reference to the accompanying drawings in which some but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
The bracing attachment device 100 is used for attaching one or more elongate braces to the form in order to brace the form in a plumb orientation while the wet concrete is being poured into the form and while the concrete is curing. Typically, two such braces are attached to the form and each extends obliquely down to engage the ground or other stable support surface. The two braces typically are orientated at 90 degrees to each other, i.e., one brace attaches to the form at a first circumferential location about the form's circumference and lies generally in a vertical plane that contains the central longitudinal axis of the form as well as the point of attachment of the brace to the form, and the other brace attaches to the form at a second circumferential location spaced 90 degrees from the attachment location of the first brace and lies generally in a vertical plane that contains the longitudinal axis of the form and the second attachment point and that is orthogonal to the plane of the first brace. However, the particular orientation and number of braces are not limitations in the present invention.
In accordance with one embodiment of the invention, the bracing attachment device 100 includes a form-engaging assembly 110 structured and arranged to be secured about the upper end portion of the column form F. Secured to the form-engaging assembly 110 is at least one toggle device 120 serving as the device that attaches a brace to the form. In the illustrated embodiment (as particularly evident from
With particular reference to
The toggle device 120 further includes an elongate first member 130 affixed to the base plate 122 and projecting from one side of the base plate in a direction generally orthogonal to a main plane in which a majority of the base plate lies. In the illustrated embodiment, the medial portion of the base plate is substantially planar, and the first member 130 is substantially orthogonal to the plane of the medial portion. However, precise perpendicularity of the first member is not essential to the functioning of the toggle device. The toggle device also includes an elongate second member 140 connected to the first member 130 by a sliding pivot connection 150 enabling the second member to slide and pivot relative to the first member. Accordingly, the second member is movable between a plurality of different positions in which the first and second members at least partially overlap, such positions including a parallel position in which longitudinal axes of the first and second members are substantially parallel to each other, a perpendicular position in which the longitudinal axes are substantially perpendicular to each other, and an oblique position in which the longitudinal axes form an oblique angle therebetween. This is further explained below.
In the illustrated embodiment, the first member 130 is a U-shaped structure such that the first member has a pair of spaced parallel legs 132, 134 with a space or slot 136 therebetween. The closed end of the U-shaped first member 130 is affixed to the base plate 122 and the open end is the opposite end remote from the base plate. At a location spaced from the base plate 122 in a direction toward the distal end of the first member 130, each leg 132, 134 has an aperture 138 formed through it, the two apertures being aligned along a pivot axis that is substantially perpendicular to the length of the first member 130 and substantially parallel to the plane of the base plate 122.
The second member 140 comprises a generally flat elongate bar having a thickness slightly less than a width of the space 136 between the legs 132, 134 of the first member 130. An elongate slot 142 is defined in the second member, a length direction of the slot extending longitudinally along the length of the second member. The second member 140 is received in the space 136 between the legs of the first member 130. A pivot pin 152 extends through the apertures 138 in the legs and through the slot 142 in the second member, thereby capturing the second member and forming the sliding pivot connection 150. The sliding pivot connection allows the second member 140 to slide in the direction defined by the slot 142 and to pivot about an axis defined by the pivot pin 152.
The spacing of the pivot pin 152 from the base plate, the length of the second member, and the length and location of the slot 142 in the second member 140 are selected so that the second member can be positioned with the pivot pin 152 all the way toward the inner end of the slot 142 (i.e., the end closer to the base plate 122) with the second member 140 oriented obliquely relative to the first member 130, such that there is a relatively small gap 160 of predetermined thickness between one end 144 of the second member 140 and the opposing surface of the base plate 122 as shown in
As will be appreciated, the pivot pin 152 also enables the second member 140 to pivot into various other positions relative to the first member 130, including a position in which the second member's longitudinal axis is substantially perpendicular to the longitudinal axis of the first member, as shown in
The second member 140 can also be pivoted into a position in which it is parallel to the first member 130, with the opposite end 146 of the second member adjacent the base plate 122 as shown in
With reference again to
As shown, the bracing attachment device 100 has two toggle devices 120 spaced apart along the strap 112. One length of the strap is affixed to the flat hook 114 at one end, and the opposite end is threaded through one of the slots 124 in the base plate 120 of one of the toggle devices, through the slot at the other end of the first toggle device, then through the slot at one end of the second toggle device, then through the slot at the other end of the second toggle device, and finally the opposite end of the strap is threaded through the tensioning device. This construction allows the toggle devices 120 to be slid along the strap to vary their spacing so as to accommodate column forms of various diameters.
Alternatively, the toggle devices could be immovably affixed to the strap at a fixed spacing distance. It is also possible to attach the toggle device(s) to a different kind of form-engaging assembly. For instance, the toggle device(s) could be nailed or otherwise affixed to a conventional wooden frame that is typically used to surround the upper end of a column form. Preferably, however, the form-engaging assembly 110 is made from a flexible, adjustable-length strap 112 as described herein, for reasons of speed and convenience in securing the device about the column form.
It is further possible that the toggle device 120 could be directly secured to, or integrated into, a column form or any other type of concrete form requiring bracing.
The use of the bracing attachment device 100 is now explained with reference to
The use of the bracing attachment device 100 according to the first approach is now explained with reference to
Next, the first toggle device 120 is put into the parallel position in which the first member 130 and second member 140 are parallel and overlapping, with the end 146 of the second member proximate to the base plate 122. The members 130, 140 are inserted through the hole in the nail plate portion 172 until the nail plate portion is abutting the base plate 122 as shown in
If there is a second toggle device 120 on the device 100, a second brace is attached to it in the same way described above.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
