Cantilevered apparatus for positioning anchor bolts and reinforcing steel bars
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2026-03-25
Smart Images
Figure CA2024050675_28112024_PF_FP_ABST
Abstract
Description
[0001] CANTILEVERED APPARATUS FOR POSITIONING ANCHOR BOLTS AND REINFORCING STEEL BARS
[0002] FIELD
[0003] The present disclosure relates in general to apparatus for positioning items such as but not limited to anchor bolts, reinforcing steel bars, and metal conduits, in formwork for constructing concrete foundations and other concrete structures.
[0004] BACKGROUND
[0005] It is commonly necessary to embed anchor bolts into concrete structures such as pile caps, foundations and footings, abutments, equipment bases, and walls, for the purposes of anchoring fixtures such as structural steel columns for commercial and industrial buildings, light standards, pipe supports, signage, handrails, traffic lights, and guard rails on bridges and roads.
[0006] It is also common for a concrete structure to be constructed in sequential stages (or “pours”), making it necessary to have reinforcing steel bars (commonly referred to as “rebar”) projecting upward from the formwork for a given stage of the construction in order to facilitate structural continuity with rebar that will be placed in the formwork for the subsequent stage of construction.
[0007] Construction drawings typically indicate the intended anchor bolt locations with reference to a selected datum point or line such as the center of an anchor bolt group or an edge or point on the concrete structure being built. For example, anchor bolt locations are commonly specified with reference to selected outside edges of concrete foundations, walls, or slabs, which also correspond to lines or surfaces on the formwork used in constructing these components of the structure.
[0008] In some concrete structures, anchor bolts are installed into holes drilled into the concrete after the concrete has cured and hardened. Anchor bolts installed into hardened concrete are commonly structurally bonded to the concrete with special epoxy adhesives that are commercially available for that specific purpose. However, it takes time and effort to drill into hardened concrete, and there is a risk that the drilling procedure could damage rebar embedded in the concrete. Regardless of the type of concrete structure being built, it is always desirable and often critically important to ensure that all required anchor bolts are held securely in position during the placement of concrete in the formwork for a given concrete structure or stage thereof, so that after the concrete has cured, the embedded anchor bolts will be properly positioned and angularly aligned to receive the fixtures they are intended to anchor. It is also often critically important to ensure that any rebar required to project from a given component or stage of the structure being built is correctly positioned in the formwork to properly lap with rebar that will be provided for an adjacent stage to be constructed in a subsequent concrete pour, and thereby to provide the intended structural continuity between the adjacent stages. Meeting these requirements entails positioning the anchor bolts (and / or rebar) accurately and securely in the formwork such that they are not susceptible to being knocked out of lateral position or angular alignment during placement of concrete in the formwork, or during related operations such as vibration of the freshly-placed concrete and finishing of exposed top surfaces of the fresh concrete. Misplacement or misalignment of anchor bolts (or rebar) can result in the need for costly and time-consuming modifications to the concrete components in which they have been cast and / or to the fixtures that the anchor bolts are intended to anchor.
[0009] There are many known methods and means for positioning anchor bolts (or rebar) in formwork. For example, one simple and common method of positioning anchor bolts in formwork is to use anchor bolt templates made from dimension lumber (e.g., 2x6s, 2x8s, etc.) or plywood, or a combination of dimension lumber and plywood. In cases where multiple anchor bolts are required for anchoring a single fixture (such as the base plate for a structural column), the appropriate bolt pattern is marked out on the template, and slightly oversize holes are drilled in the template to receive the anchor bolts. The bolts are then inserted into the holes in the templates, typically along with nuts and washers or other means to set the height that the bolts will project above the finished concrete. The assembly of the wooden template and anchor bolts is temporarily secured to the formwork, and then concrete can be placed in the formwork.
[0010] Such common methods for setting anchor bolts into position over formwork are satisfactory if carried out with proper care. Unfortunately, however, that often does not happen, and the result is anchor bolts that have been cast into the concrete in the wrong position in one or both lateral directions, and / or out of angular alignment, due to factors such as inaccurate marking and drilling of bolt-receiving holes in the wooden templates, and inaccurate or insufficiently secure positioning of the templates on the formwork.
[0011] Various types of anchor bolt positioning devices are commercially available, but they can be expensive or comparatively difficult to use. Accordingly, there is a need for an anchor bolt positioning apparatus that is inexpensive and simple to use, while reducing the chances of error with respect to the positioning of anchor bolts in finished concrete structures or components thereof, and which preferably can also be used to retain projecting rebar in position in the formwork during concrete placement. In addition, there is a particular need for an apparatus that can be used to position anchor bolts and / or rebar projections in situations where only one formwork component is conveniently available for mounting and supporting the apparatus - in contrast to the common case of formwork for a concrete wall, a pile cap, or a comparatively small equipment pedestal where an anchor bolt positioning apparatus can conveniently span across formwork panels on opposite sides of the wall, pile cap, or pedestal.
[0012] BRIEF SUMMARY OF THE DISCLOSURE
[0013] The present disclosure teaches a cantilevered bolt-positioning apparatus for holding anchor bolts (or reinforcing steel bars, conduits, or other articles that might need to be embedded) in desired lateral positions and angular alignments within a formwork assembly while being cast into a concrete foundation or concrete structure.
[0014] In a first embodiment, the cantilevered bolt-positioning apparatus comprises:
[0015] • an elongate main body having a first end and a second end, and comprising two side members defining a longitudinal slot for receiving one or more bolt holders longitudinally movable therewithin; and
[0016] • a single mounting bracket comprising a lower section rigidly mountable to the formwork, and an upper section connected to the lower section and configured for engagement with the main body such that the main body will be longitudinally movable relative to the single mounting bracket, while also being constrained by the upper section against longitudinal or lateral rotation and vertical movement relative to the upper section. When the lower section of the mounting bracket is mounted to the formwork, with the main body longitudinally movably engaging the upper section of the mounting bracket:
[0017] • the longitudinal position of the main body relative to the mounting bracket and the formwork will be adjustable to cantilever a selected portion of the length of the main body from the mounting bracket, to extend over the formwork cavity; and
[0018] • the longitudinal position, relative to the main body, of any movable bolt holder disposed in the longitudinal slot of the main body will be adjustable by longitudinally moving the bolt holder longitudinally relative to the main body.
[0019] The connection between the upper and lower sections of the mounting bracket is designed to transfer, from the upper section to the lower section, reaction forces and bending moments induced in the upper section by the weight of the cantilevering main body and any bolt holders, bolts, steel reinforcing bars, or other elongate articles carried thereby.
[0020] In a second embodiment, the cantilevered bolt-positioning apparatus is generally similar to the first embodiment except that the main body is fixed to or integral with the mounting bracket.
[0021] BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Embodiments in accordance with the present disclosure will now be described with reference to the accompanying Figures, in which numerical references denote like parts, and in which:
[0023] FIGURE 1 is a first schematic perspective showing two bolt-positioning apparatuses in accordance with the present disclosure, each supporting two anchor bolts, and each being mounted to and cantilevered from a component of a formwork assembly, with the portion of the apparatus carrying the anchor bolts projecting over the formwork assembly.
[0024] FIGURE 2 is a second schematic perspective of the formwork-mounted bolt-positioning apparatuses shown in FIG. 1, looking from a viewpoint outside the formwork assembly. DETAILED DESCRIPTION
[0025] FIGS. 1 and 2 illustrate two identical examples of an embodiment 300 of a boltpositioning apparatus in accordance with the present disclosure, schematically shown mounted to a formwork component 360 (shown by way of non-limiting example as a side panel of a formwork assembly) so as to partially extend, in cantilever fashion, over the formwork assembly. In this illustrated embodiment, each bolt-positioning apparatus 300 comprises three primary components:
[0026] • an elongate main body 310 having a first (or outer) end 310A and a second (or inner) end 310B, optionally having an outer end cap 318A on outer end 310A and optionally having an inner end cap 318B on outer end 310B, and defining a longitudinal slot 315 bounded by a pair of elongate side members 314, wherein longitudinal slot 315 has a first (or outer) end 315A and a second (or inner) end 315B;
[0027] • one or more elements for holding or positioning anchor bolts, steel reinforcing bars, or other elongate articles (which said elements are alternatively referred to herein simply as bolt holders), wherein at least one of the one or more bolt holders is: o a longitudinally movable (relative to main body 310) bolt holder 320 slidably disposable within longitudinal slot 315 in main body 310; or o a fixed (relative to main body 310) bolt holder integral with an inner end cap 318B provided on inner end 310B of main body 310; and
[0028] • a single mounting bracket 330 having a lower section 330L rigidly mountable to a formwork component, and an upper section 330U connected to lower section 330L and configured for engagement with main body 310 such that: o main body 310 will be longitudinally movable relative to bracket 330, while also being constrained by upper section 330U of bracket 330 against longitudinal or lateral rotation and against vertical movement relative to upper section 330U; and o a selected portion of main body 310, carrying the one or more (movable or fixed) bolt holders, can project in cantilever fashion from bracket 330 to position the one or more bolt holders over the formwork cavity into which concrete is to be placed.
[0029] In the illustrated embodiment, movable bolt holders 320 are provided with retention means for setting movable bolt holders 320 in desired vertical positions relative to main body 310. By way of non-limiting example (and as illustrated in FIG. 1), such retention means may be provided in the form of a flange 322 extending laterally outward from an upper region of movable bolt holder 320 such that the flange will rest on an upper surface of the main body. Movable bolt holders 320 are also provided with connection means for fixing movable bolt holders 320 in desired longitudinal positions on main body 310. As shown by way of nonlimiting example in FIG. 1, such connection means may comprise holes 324 provided in flanges 322 for receiving screws or nails (not shown) to fasten flanges 322 (and thus movable bolt holders 320) to main body 310.
[0030] The particular way in which upper section 330U of mounting bracket 330 is configured to enable longitudinally-movable engagement of main body 310 (as described above) will be a matter of design choice, as this functionality can be provided in multiple different ways using known technologies without the exercise of inventive ingenuity. By way of non-limited example only, FIG. 2 shows upper section 330U providing this functionality in the form of rectangular slide channels 336 sized to receive rectangular side members 314 of main body 310 with minimal clearance, such that side members 314 are slidable within slide channels 336 while being substantially constrained against rotation about a horizontal axis relative to bracket 330, by virtue of slide channels 336 being designed to have sufficient length in the direction parallel to side members 314 to provide bracket 330 with sufficient structural strength to resist reaction forces and bending moments induced in side members 314 by the weight of cantilevering main body 310 and any anchor bolts 340 being supported thereby.
[0031] The appropriate configuration of lower section 330L of mounting bracket 330 will be a matter of engineering design to ensure that lower section 330L can resist reaction forces and bending moments resisted by upper section 330U of bracket 330 (as described above) and transferred thereby to lower section 330L, which in turn must transfer such forces and bending moments to the formwork structure. FIG. 2 illustrates, by way of non-limiting example, lower section 330L comprising a vertical abutment plate 331 configured to abut an outside face of a formwork component 360, with vertical stiffeners 335 provided between abutment plate 331 and a lower member 338 of upper section 330U of bracket 330 to provide lower section 330L with increased stiffness and structural continuity with upper section 330U, and with fastener holes 333 being provided in abutment plate 331 for receiving fasteners (not shown) for securing fastening abutment plate 331 (and, thereby, bracket 330) to formwork component 360. In alternative embodiments, stiffeners 335 might not be necessary if abutment plate 331 has sufficient thickness and strength to safely resist the applied forces and moments.
[0032] Appropriate fasteners for fastening abutment plate 331 to formwork panel 360 could range from nails or small wood screws to more robust fasteners such as lag screws, depending on factors including the total weight of the cantilevered bolt-positioning apparatus and the bending moment induced thereby, as well as the number of fasteners used and the physical characteristics of the formwork component.
[0033] In the illustrated embodiment, mounting bracket 330 is provided with connection means for fixing main body 310 in a desired longitudinal position relative to bracket 330. As shown by way of non-limiting example in FIG. 2, such connection means may comprise holes 334 provided in a plate 332 defining the top of slide channels 336 for receiving screws or nails (not shown) to interconnect bracket 330 and side members 314 of main body 310.
[0034] One or more movable bolt holders 320 may be positioned in longitudinal slot 315 in main body 310, and an anchor bolt 340 may be installed in each movable bolt holder 320 (and in any fixed bolt holder integral with inner end 310B of main body 310), either before or after cantilevered bolt-positioning apparatus 300 has been mounted onto the formwork assembly. Anchor bolts 340 may be conveniently retained in their respective bolt holders by means of nuts 342 installed on the threaded portions of bolts 340 extending above the bolt holders (or by any other suitable means).
[0035] To use cantilevered bolt-positioning apparatus 300, main body 310 is positioned on the formwork for the concrete structure or component into which anchor bolts 340 are to be embedded, with mounting bracket 330 rigidly mounted to a selected component of the formwork. Main body 310 is rigidly mounted on the formwork with longitudinal slot 315 in main body 310 at a desired angular orientation relative to the formwork, such that the portion of main body 310 carrying bolt holders cantilevers from the edge of the formwork, over the interior of the formwork.
[0036] The desired angular orientation of longitudinal slot 315 relative to the formwork might most commonly be a perpendicular orientation. However, situations are conceivable where the desired angular orientation may be other than perpendicular, and such situations may be accommodated within the scope of the present disclosure using variant embodiments of mounting bracket 330. For example, mounting bracket 330 may incorporate swivel means (not shown) to facilitate some degree of angular adjustment of main body 310 relative to lower section 330L of mounting bracket 330 (and thus relative to the formwork). Optionally, the swivel means may also incorporate a threaded mechanism facilitating some degree of height adjustment for main body 310 relative to bracket 330 and the formwork. The angular orientation of main body 310 relative to lower section 330L and the formwork may be fixed by any suitable means.
[0037] In instances where a bolt-positioning apparatus 300 is being used to retain one or more vertically-projecting reinforcing steel bars in their correct horizontal positions during concrete placement, the rebars will typically have been installed in the formwork already, in which case apparatus 300 may be positioned over the projecting rebars so that they pass through longitudinal slot 315 of apparatus 300 to then receive suitably- sized movable bolt holders 320 (and / or one or more projecting rebars can be passed through suitably-sized holes of any fixed bolt holders integrally provided in inner end 310B or main body 310), whereafter apparatus 300 can be rigidly mounted to the formwork as previously described.
[0038] To correctly locate anchor bolts 340, construction drawings typically show the spacing between anchor bolts and the distance from the outside edge of the concrete to either one of the anchor bolts or to the center point between anchor bolts. The specified bolt spacing can be set by affixing bolt holders 320 at the appropriate spacing / distance along main body 310 of apparatus 300. Optionally, main body 310 may have a printed linear scale to facilitate quick and accurate positioning of movable bolt holders 320 within slot 315. Main body 310 can then be moved longitudinally relative to mounting bracket 330 until the locations of movable bolt holders 320 relative to main body 310 correspond to the correct positions for bolts 340 relative to a selected reference datum such as (by way of non-limiting example) an inside edge of the formwork (corresponding to an outside edge of the concrete element being constructed). Mounting bracket 330 can be connected to main body 310 by suitable means as previously described, with main body 310 cantilevering to a desired extent over the formwork, to fix the position of main body 310 in the desired longitudinal location relative to mounting bracket 300 and the formwork. At this stage, bolt-positioning apparatus 300 is fully assembled and securely mounted on the formwork assembly, which is then ready to receive concrete. The above-described sequencing of the steps in assembling and mounting boltpositioning apparatus 300 to a formwork assembly is by way of example only, and the required steps could be performed in different sequences to achieve desired results. To provide one example, the one or more bolt holders 320 could be installed in and fixed to main body 310 before apparatus 300 is mounted on the formwork. In one embodiment, lower section 330L of mounting bracket 330 could be removable, and could be mounted onto the formwork first, with main body 310 then being installed in upper section 330U of mounting bracket 330. Depending on the congestion of reinforcing steel bars in the formwork, anchor bolts 340 may be installed in the movable and / or fixed bolt holders either before or after apparatus 300 has been set in position.
[0039] After the concrete wall, foundation, slab, or other structure has been cast and has sufficiently cured, bolt-positioning apparatus 300 can be removed by removing nuts 342 from projecting anchor bolts 340, removing the nails, screws, staples, lag screws, or other fastening means used to fix mounting brackets 330 to the formwork, and then lifting apparatus 300 off of the concrete structure.
[0040] Bolt-positioning apparatus 300 and its various components may be fabricated or formed from any suitable material or combination of materials, including but not limited to pressed metal, extruded metal, timber, fabricated / laminated timber, formed plastic, wax-coated cardboard, and / or pressed wood fiber. Depending on the material or materials used, apparatus 300 or components thereof may be reusable. Alternatively, the material or materials used may dictate that apparatus 300 is suitable for only one use only, such as when its components are made from cardboard or similar materials, in which case apparatus 300 could be simply tom off the formwork (or knocked off with a hammer or other suitable tool) after the concrete has cured, and then suitably disposed of.
[0041] The foregoing text and FIGS. 1 and 2 describe and illustrate embodiments of a cantilevered bolt-positioning apparatus incorporating an elongate main body 310 that is slidably received in mounting bracket 330, a movable bolt holder 332 positioned in the longitudinal slot 315 of main body 310, and an inner end cap 318B on inner end 318 of main body 310 that integrally incorporates a fixed bolt holder. However, not all embodiments in accordance with the present disclosure necessarily include all of these features. For example:
[0042] • In one variant embodiment, there is no fixed bolt holder in inner end cap 318B. • In another variant embodiment, main body 310 is not longitudinally movable relative to mounting bracket 330, but instead is fixed to or integral with bracket 330.
[0043] Optionally, upper section 330U of mounting bracket 330 may incorporate alignment guide means such as a sighting window, grooves, or notches to help align bracket 330 with surveyors’ marks on the formwork to assist a user in positioning apparatus 300 in the correct location on the formwork.
[0044] Optionally, mounting bracket 330 may incorporate swivel means configured to allow for some degree of angular adjustment of main body 310 relative to bracket 330 and the formwork to which it is mounted. The desired angular orientation of main body 310 may be fixed by means of suitable fasteners such as (for example) nails, screws, or staples. Optionally, the swivel means may incorporate a threaded mechanism to facilitate some degree of height adjustment for main body 310 relative to mounting bracket 330 and the formwork. For example, a variant of mounting bracket 330 could comprise a variant of upper section 330U that can swivel relative to a variant of lower section 330L while also being height-adjustable relative thereto, and while maintaining the ability to resist, and to transfer to lower section 330L, such loads and bending moments as may be induced in side members 314 by the weight of cantilevering main body 310 and any anchor bolts 340 being supported thereby.
[0045] # # # # # # #
[0046] It will be readily appreciated by persons skilled in the art that various modifications to embodiments in accordance with the present disclosure may be devised without departing from the scope of the present teachings, including modifications that use equivalent structures or materials hereafter conceived or developed.
[0047] It is especially to be understood that the scope of the present disclosure is not intended to be limited to described or illustrated embodiments, and that the substitution of a variant of any claimed or illustrated element or feature, without any substantial resultant change in functionality, will not constitute a departure from the scope of the disclosure.
[0048] In this patent document, any form of the word “comprise” is to be understood in its non-limiting sense to mean that any element or feature following such word is included, but elements or features not specifically mentioned are not excluded. A reference to an element or feature by the indefinite article "a" does not exclude the possibility that more than one such element or feature is present, unless the context clearly requires that there be one and only one such element or feature. Any use herein of any form of the terms “affix”, “connect”, “mount”, or any other term describing an interaction between elements is not intended to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements such as through secondary or intermediary structure.
[0049] Wherever used in this document, the terms “typical” and “typically” are to be understood and interpreted in the sense of being representative of common usage or practice, and are not intended to be understood or interpreted as implying essentiality or invariability.
Claims
WHAT IS CLAIMED IS:
1. An apparatus for positioning anchor bolts, steel reinforcing bars, or other elongate articles in formwork defining a cavity for receiving fluid concrete for a concrete structure, said apparatus comprising:(a) an elongate main body having a first end and a second end, and comprising two side members defining a longitudinal slot for receiving one or more bolt holders longitudinally movable there within; and(b) a single mounting bracket comprising:(b.1) a lower section rigidly mountable to the formwork; and(b.2) an upper section connected to the lower section and configured for engagement with the main body such that the main body will be longitudinally movable relative to the single mounting bracket, while also being constrained by the upper section against longitudinal or lateral rotation and vertical movement relative to the upper section; wherein:(c) when the lower section of the mounting bracket is mounted to the formwork, with the main body longitudinally movably engaging the upper section of the mounting bracket:(c.1) the longitudinal position of the main body relative to the mounting bracket and the formwork will be adjustable to cantilever a selected portion of the length of the main body from the mounting bracket, to extend over the formwork cavity; and(c.2) the longitudinal position, relative to the main body, of any movable bolt holder disposed in the longitudinal slot of the main body will be adjustable by longitudinally moving said bolt holder longitudinally relative to the main body; and(d) the connection between the upper and lower sections of the mounting bracket is designed to transfer, from the upper section to the lower section, reaction forces and bending moments induced in the upper section by the weight of thecantilevering main body and any bolt holders, bolts, steel reinforcing bars, or other elongate articles carried thereby.
2. An apparatus for positioning anchor bolts, steel reinforcing bars, or other elongate articles in formwork defining a cavity for receiving fluid concrete for a concrete structure, said apparatus comprising:(a) an elongate main body having a first end and a second end, and comprising two side members defining a longitudinal slot for receiving one or more bolt holders longitudinally movable there within; and(b) a single mounting bracket comprising:(b.1) a lower section rigidly mountable to the formwork; and(b.2) an upper section connected to the lower section; wherein:(c) the first end of the main body is fixed to or integral with the mounting bracket;(d) when the lower section of the mounting bracket is mounted to the formwork:(c.1) the main body will be cantilevered from the mounting bracket to extend over the formwork cavity; and(c.2) the longitudinal position, relative to the main body, of any movable bolt holder disposed in the longitudinal slot of the main body will be adjustable by longitudinally moving said bolt holder longitudinally relative to the main body; and(d) the connection between the upper and lower sections of the mounting bracket is designed to transfer, from the upper section to the lower section, reaction forces and bending moments induced in the upper section by the weight of the cantilevering main body and any bolt holders, bolts, steel reinforcing bars, or other elongate articles carried thereby.
3. The apparatus as in Claim 1 or Claim 2, further comprising a fixed bolt holder integral with an inner end cap provided on the inner end of the main body.
4. The apparatus as in any one of Claims 1-3 wherein the mounting bracket incorporates swivel means facilitating angular adjustability of the main body relative to the lower section of the mounting bracket and the formwork.
5. The apparatus as in any one of Claims 1-4 wherein the mounting bracket incorporates height adjustment means facilitating height adjustability of the main body relative to the mounting bracket and the formwork.
6. The apparatus as in Claim 5 wherein the height adjustment means incorporates a threaded mechanism.
7. The apparatus of Claim 4 wherein the swivel means incorporates height adjustment means facilitating a degree of height adjustability of the main body relative to the mounting bracket and the formwork, and wherein said height adjustment means incorporates a threaded mechanism..
8. The apparatus as in any one of Claims 1-7 wherein the upper section of the mounting bracket incorporates alignment guide means to assist a user in aligning the mounting bracket with surveyors’ marks on the formwork relating to intended positions of anchor bolts to be embedded in the concrete structure.