COIlMPSIBftE INSIDE CORNER FORM

Background of the Invention

[00011 This application claims priority to United States Patent Application Serial No. 60/722,632, filed September 30, 2005. [00021 Field of the Invention

[00031 The invention relates generally to apparatus used in forming concrete structures and, more specifically, to a concrete forming apparatus for use in forming corners of a concrete structure.

[00041 Background of the Prior Art

[00051 Concrete forming apparatus is in wide use in the construction of buildings, bridges, and other concrete structures. A common system for forming concrete structures uses a plurality of form components that are adapted to be assembled into a wide variety of configurations to conform to virtually any architectural requirement. Such forming apparatus components are typically made of metal so that they are strong enough to support the heavy weight of poured concrete and durable so that the components can be reused many times. [00061 One of the configurations that is most frequently encountered in constructing concrete structures is the right angle corner. To form a wall having a corner, two sets of forms must be constructed, an inside corner form and a corresponding outside corner form that is spaced from the inside corner form by the thickness of the wall to be formed between the two forms. Once the concrete has been poured and has set sufficiently, the forms must be stripped from the wall. This usually does not present a problem on the outside corner form where there is sufficient room to separate the form components and release them from the wall. On the inside corner form, however, the form components frequently are difficult to disassemble and release from the wall because of the inside corner geometry and because of the pressure that is exerted on the forms by the poured concrete.

[00071 Another issue faced in the forming of concrete wall corners is that long runs of concrete form assemblies will often meet at a corner where the form components must fit together with close tolerances. During the actual construction of a concrete structure, there are inevitably variations in the assembly of the components and preparation of the site that must be accommodated. Conventional corner forming apparatus have required the use of

hancftώti%aø ^β rδHrsffim"srTφiϊfeslSfo1ime-consuming and can require a relatively high level of skill to build. Additionally, the hand-built spacers or shims frequently cannot be reused and so must be constructed anew each time the forms are reset. [00081 One approach to forming corners has been the use of form components that are fabricated with the predetermined angle, most commonly a right angle (90°). These form components suffer from the disadvantage of having a shape that prevents them from lying flat during shipping and storage. Further, such fabricated corner forms cannot be stripped from an inside corner until the adjacent form components have been removed. [00091 It is advantageous to have the ability to interconnect the various components of the corner forming apparatus in a wide variety of configurations without unduly multiplying the number of distinct components that are required to assemble the corner forming apparatus of the desired diversity of dimensions and which will readily accommodate the typical range of variations found in the field.

Summary of the Invention

[0010] The invention consists of an inside corner concrete form that is hinged to facilitate setting and stripping of the form. The form includes two cooperating form subassemblies that are hinged to permit folding of each of the form assemblies during setting and stripping of the forms. A first form assembly includes two sub-forms that are interconnected by a hinge. When set to form a concrete structure, the two sub-forms of the first subassembly are aligned to present a planar surface against which the plastic concrete is poured and set. After the plastic concrete has set, the sub-forms are stripped from the wall and can be folded relative to each other about the pivot axis of the pin. In a preferred embodiment, the two-sub forms are folded to substantially a right angle relative to each other. The second form subassembly also includes two sub-forms that are interconnected by a hinge as in the first form subassembly and a second, inside corner sub-form, to create a subassembly that is foldable between a setting position which is substantially L-shaped in transverse cross section and a stripped position which is substantially J- shaped in transverse cross-section. When set to form a concrete structure, the two sub-forms of the second subassembly are aligned relative to the hinge to present a first planar surface and a second planar surface that is at an obtuse angle relative to the first planar surface. After the concrete has set, the second sub-form is folded or pivoted about the hinge toward the first sub-

foπrff?^ Sα.n&e. _' tMWMiϊϊgfefSs .s'paέ ^" JH' 1R>M the set concrete structure, the obtuse angle provides clearance to permit pivoting of the second sub-form.

[0011] In the folded configuration, the transverse extension of each the two subassemblies are reduced so as to provide worker access between the subassemblies and the formed concrete structure. The novel inside corner form of the present invention eliminates the need for shims or other worker-made adaptations and is easily set up and stripped in close quarter situations.

[0012] An object of the invention is to provide a form apparatus for forming corners of a concrete structure that can be easily and readily stripped from the formed wall.

[0013] A further object of the invention is to provide a form apparatus for forming corners of a concrete structure that are provided in a limited range of dimensions to allow selection in the field to reduce the need for hand-built spacers or shims without requiring a large inventory of components.

[0014] These and other objects of the invention will be made apparent to those skilled in the art upon a review and understanding of this specification, the associated drawings, and the appended claims.

Brief Description of the Drawings

[0015] Fig. 1 is a top view of the inside corner form of the present invention shown in the setting position is assembly with other modular form components for forming an inside corner of a concrete structure.

[0016] Fig. 2 is an enlarged detail view of a corner element of the inside corner form of the present invention.

[0017] Fig. 3 is a plan view corresponding to Fig.1 after the inside corner of the concrete structure has been poured and set and the inside corner form of the present invention stripped and folded.

Detailed Description of Preferred Embodiments

[0018] Referring to the drawings, there is illustrated in Fig. 1, generally at 10, an inside corner form of the present invention. The inside corner form 10 includes two subassemblies, a first subassembly, illustrated generally at 12, and a second subassembly, illustrated generally at 14. The first subassembly includes a first planar wall form 16 and a second planar wall form 18 that are interconnected by a hinge form assembly 20 that is releasably secured to the wall forms 16

and tf ^r 8£y tof Thus the two wall forms 16 and 18 are pivotal relative to each other about the axis of the hinge at 24. In a preferred embodiment, the end of the wall form 18 opposite the hinge has an end face that is perpendicular to the concrete structure being formed and is secured to a reverse bias form 25 having an angled end face with an obtuse bias of 135°.

[0019] The second subassembly 14 also includes a first planar wall form 26 and a second wall form 28 that are interconnected by a hinge form assembly 30 that is releasably secured to the wall forms 26 and 28 by nut and bolt combinations 32. Thus the two wall forms 26 and 28 are pivotal relative to each other about the axis of the hinge at 34. In a preferred embodiment, the end of the wall form 28 opposite the hinge is has an angled end face with a 45° acute bias. [0020] A corner assembly 36 is releasably secured to the biased edge of the wall form 28 by nut and bolt combinations 38. The corner assembly 36 has a first wall form face 40 and a second wall form face 42 that is oriented at an obtuse angle relative to the first wall form face 40, as best illustrated in Fig. 2. The other end face 48 of the corner assembly 36 is parallel to the first wall form face 40 and is releasably secured to the perpendicular end face of a bias form 25 by nut and bolt combinations 50, the bias form 35 also having an opposite angled end face with an acute bias of 45° which, upon assembly as illustrated in Fig. 1, is secured to the reverse bias face of the reverse bias form 25 by nut and bolt combinations 37.

[0021] In assembly to form an inside corner of a concrete structure, as illustrated in Fig. 1, the outer surface of the concrete structure is formed against the face panels of a plurality of planar concrete forms 52. The form subassemblies 12 and 14 are positioned a spaced-apart distance from and facing the forms 52. A plurality of tie rod assemblies 54 are used to hold the forms 12, 14, and 52 at their pre-selected spaced-apart distance. With the forms assembled, plastic concrete is poured in the space between the forms and allowed to set. In the preferred embodiment illustrated in Fig. 1, a right-angle wall segment is formed having an inside corner defined by the corner assembly 36.

[0022] Once the concrete is set, the forms are stripped from the formed concrete structure 56 (Fig. 3). This is accomplished by removing the nut and bolt combinations 37 that interconnect the two form subassemblies 12 and 14 byway of the reverse bias form 25 and the bias form 35, respectively, and the associated tie rods 54. The first subassembly 12 is then pulled away from

the toward the first planar wall section 16 about hinge 20. Next, the corner assembly 36 and its attached second wall forms 28 and 35 are folded about hinge 30 toward the first wall form 26 and moved away from the formed concrete structure. Note that the obtuse angle of the corner assembly 36 is required in order to strip the second subassembly 14 because the pivot 38 of the hinge 30 is spaced away from the formed concrete surface.

[0023] Although the invention has been described with respect to a preferred embodiment thereof, it is to be also understood that it is not to be so limited since changes and modifications can be made therein which are within the full intended scope of this invention as defined by the appended claims.