Self-adjusting heel joint connector and method of securing a heel joint
10253495 ยท 2019-04-09
Inventors
Cpc classification
E04B7/045
FIXED CONSTRUCTIONS
International classification
E04B7/04
FIXED CONSTRUCTIONS
Abstract
A self-adjusting heel joint connector for securing roof structural members, without the need for a conventional birdsmouth cut or toe-nailing. The connector is slideably insertable between a bottom surface of a preset rafter and the top of a supporting wall plate at a heel joint and is capable of self-adjusting to the precise preset rafter pitch. The connector includes a framing member securable to the top of the supporting wall plate, and a support member rotatably coupled to the framing member and freely rotatable about an axis of rotation perpendicular to a longitudinal axis of the framing member. The framing member is securable to the angled rafter and an adjacent joist/tie member, as well as to the supporting wall plate, at the heel joint, and the rafter is supported by a substantially flat mating surface of the support member which extends in a direction perpendicular to a vertical leg of the framing member. The connector provides restraint from lateral movement and wind uplift, and provides for full vertical rafter load transfer partly through the framing member vertical leg of the connector and partly through the adjacent joist/tie member directly to the top of the supporting wall plate over a uniform distributed area, while transferring thrust force in the rafter to the adjacent joist/tie member. The support member further provides additional support for dead and live loads, while eliminating the need for a conventional birdsmouth cut at the heel joint.
Claims
1. A method of securing a heel joint connecting structural members in a building roof structure, comprising: providing a heel joint connector comprising a framing member having a substantially flat base surface and a vertical leg, the flat base surface adapted for securing the framing member to a top surface of a wall plate, the vertical leg attached to or integral with the flat base surface and positioned at approximately a right angle thereto, the vertical leg adapted for securing the framing member to a rafter and an adjacent joist/tie at a heel joint; and a support member rotatably coupled to the framing member vertical leg and having a substantially flat surface portion for mating with a bottom surface of the rafter, wherein the support member is freely rotatable within a predetermined rafter pitch range about an axis of rotation perpendicular to a longitudinal axis of the framing member vertical leg; slideably inserting the heel joint connector between a bottom surface of a preset rafter and a top surface of a wall plate; moving the heel joint connector laterally along the wall plate top surface in the direction of an exterior stud supporting the wall plate while causing the support member to rotate to a pitch of the preset rafter until the support member flat surface portion fully contacts the rafter bottom surface; securing the connector framing member to the wall plate top surface via the framing member flat base surface; securing the connector framing member vertical leg to the rafter and an adjacent joist/tie; and securing the support member to the framing member to prevent further rotation of the support member with respect to the framing member vertical leg, thereby securing the heel joint.
2. The method of claim 1 wherein the framing member vertical leg includes a plurality of through-holes for receiving fasteners to secure the framing member to the rafter and adjacent joist/tie, the plurality of through-holes oriented in a plurality of angled row lines along the longitudinal axis of the framing member vertical leg, and wherein the step of securing the connector framing member vertical leg to the rafter and an adjacent joist/tie comprises: driving fasteners through the framing member vertical leg plurality of through-holes and through the rafter and joist/tie.
3. The method of claim 2 wherein each through-hole in a row line is spaced a predetermined distance S1 along the row line, and each row line is spaced a predetermined distance S2 from each adjacent row line, wherein S1 is not equal to S2.
4. The method of claim 2 wherein each through-hole in a row line is spaced a predetermined distance S3 in a vertical dimension, wherein S3=(S1sin ), where is an angle formed between the row line and a line intersecting the row line and extending parallel to a top edge of the framing member vertical leg.
5. The method of claim 3 wherein the through-hole closest to the heel joint in a bottom row line is spaced a predetermined distance S4 from a top surface of the support member flat surface portion when the support member flat surface portion is rotated to a pitch of 4/12, wherein S4 is equal to S2.
6. The method of claim 2 wherein each through-hole in a row line is spaced a predetermined distance S5 from an adjacent edge of the framing member vertical leg.
7. The method of claim 1 wherein contact between the support member flat surface portion and the rafter bottom surface as the connector is moved laterally along the wall plate top surface causes the support member to rotate to the pitch of the preset rafter.
8. The method of claim 1 wherein the framing member flat base surface includes a plurality of through-holes for receiving fasteners to secure the framing member to a wall plate top surface, wherein the step of securing the connector framing member to the wall plate top surface via the framing member flat base surface comprises: driving fasteners through the framing member flat base surface plurality of through-holes into the wall plate top surface.
9. The method of claim 2 wherein the framing member vertical leg has no protrusions extending therefrom, and further comprising the steps of: positioning adjacent faces of the rafter and joist/tie flush relative to the other; and driving fasteners through the framing member vertical leg plurality of through-holes into the rafter and joist/tie to secure the heel joint.
10. The method of claim 1 wherein the support member and framing member are each fabricated from a single sheet of gage steel, formed from cast steel or formed from forged metal, and wherein each of the framing member, support member and rotatable coupling includes a corrosion-preventing protective coating.
11. A self-adjusting heel joint connector for connecting structural members in building roof structures, comprising: a framing member having a substantially flat base surface and a vertical leg, the flat base surface adapted for securing the framing member to a top surface of a wall plate, the vertical leg attached to or integral with the flat base surface and positioned at approximately a right angle thereto, the vertical leg including a plurality of through-holes for receiving fasteners to secure the framing member to a rafter and an adjacent joist/tie at a heel joint, the plurality of through-holes oriented in a plurality of angled row lines along a longitudinal axis of the framing member vertical leg; and a support member rotatably coupled to the framing member vertical leg and having a substantially flat surface portion for mating with a bottom surface of a rafter preset at a selected pitch, the support member freely rotatable about an axis of rotation perpendicular to the longitudinal axis of the framing member vertical leg.
12. The connector of claim 11 wherein each through-hole in a row line is spaced a predetermined distance S1 along the row line, and each row line is spaced a predetermined distance S2 from each adjacent row line, wherein S1 is not equal to S2.
13. The connector of claim 11 wherein each through-hole in a row line is spaced a predetermined distance S3 in a vertical dimension, wherein S3=(S1sin ), where is an angle formed between the row line and a line intersecting the row line and extending parallel to a top edge of the framing member vertical leg.
14. The connector of claim 12 wherein the through-hole closest to the heel joint in a bottom row line is spaced a predetermined distance S4 from a top surface of the support member flat surface portion when the support member flat surface portion is rotated to a pitch of 4/12, wherein S4 is equal to S2.
15. The connector of claim 11 wherein each through-hole in a row line is spaced a predetermined distance S5 from an adjacent edge of the framing member vertical leg.
16. The connector of claim 11 wherein the support member is self-adjustable to a preset rafter pitch as the heel joint connector is slideably inserted between the bottom surface of the rafter and the wall plate top surface and moved laterally along the wall plate top surface in the direction of an exterior stud supporting the wall plate until the support member flat surface portion fully contacts the rafter bottom surface.
17. The connector of claim 11 wherein the framing member flat base surface includes a plurality of through-holes for receiving fasteners to secure the framing member to a wall plate top surface.
18. The connector of claim 11 wherein the framing member vertical leg has no protrusions extending therefrom, the framing member vertical leg permitting the rafter and adjacent joist/tie to be positioned flush relative to the other for receiving fasteners driven through the framing member vertical leg into the rafter and joist/tie to secure the heel joint.
19. The connector of claim 11 wherein the support member and framing member are each fabricated from a single sheet of gage steel, formed from cast steel or formed from forged metal, and wherein each of the framing member, support member and rotatable coupling includes a corrosion-preventing protective coating.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims.
(2) The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:
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DESCRIPTION OF THE EMBODIMENT(S)
(15) In describing the embodiments of the present invention, reference will be made herein to
(16) The present invention addresses the roof to wall heel connection in modern housing construction, more particularly wood frame construction, and specifically the roof heel joint (where the roof rafters bear on the supporting wall). It is at this connection that dead & live loads, rafter thrust force, plus wind/hurricane & seismic forces are transferred.
(17) The joint at the intersection of the roof rafter, joist/tie, blocking, wall plate and wall studs is commonly referred to as the heel joint. The heel joint is one of the most significant joints in the entire building structure, and represents the point where the roof's dead and live loads with rafter thrust force are combined with wind/hurricane loads, exposing the heel joint to uplift and overturning forces in all directions. It is at this junction that the aforementioned loads are transferred to the exterior supporting, bracing and shear walls.
(18) Conventionally, mating an angled rafter securely with the top wall plate at the heel joint is achieved using a birdsmouth cut or seat in the rafter. The standard construction is to notch the bottom of the rafter with an angular cut to accommodate the selected roof pitch and having toe-nails to connect to the top wall plate. To assure proper fit, the joint requires a skilled carpenter for accuracy to layout each rafter and to provide a cut allowing for full surface contact between the bottom of the rafter and the top of the supporting wall plate. Further, toe-nailing of the rafter to the supporting wall plate is required, which leads to splitting at the rafter load bearing surface. These conditions weaken the carrying capacity of the joint. Also, the birdsmouth cut reduces the cross-sectional area of the rafter. Once the rafter is positioned, the proper fastener positioning is left up to the craftsmen who would have to measure a layout on each rafter.
(19) The present invention provides a self-adjusting heel joint connector which provides for full load transfer from the bottom of a preset rafter to the top of the supporting wall plate without the need for a conventional birdsmouth cut or toe-nailing of the rafter to the supporting wall plate, or the measuring of a proper fastener layout on each rafter, which are generally required in the prior art. The present invention has the capability to self-adjust to the precise preset pitch of the rafter. The design of the connector is such that the connector can provide for a pitch range of 6/12 to 12/12 (and the infinite fractions in between) for a conventional 24 wall plate, and 3/12 to 12/12 (and the infinite fractions in between) for a conventional 26 wall plate. Further, the unique design is such that the vertical rafter dead and live loads, as well as the vertical component of the thrust force, are transferred partly through the framing member vertical leg of the connector and partly through the adjacent joist/tie directly to the top of the supporting wall plate over a uniform distributed area, while the rafter thrust force is transferred to the adjacent joist/tie member, and the wind lateral and uplift load is transferred to the wall plate, providing a complete structural system.
(20) The self-adjusting heel joint connector of the present invention includes a support member rotatably coupled to a framing member. The support member is freely rotatable with respect to the framing member about an axis perpendicular to the longitudinal axis of the framing member within a predetermined rafter pitch range, which allows the heel joint connector to self-adjust to the precise pitch of the rafter during the placing process, providing for full surface contact and direct vertical load transfer to the supporting wall plate. In one method, the heel joint connector is slidably inserted by hand between the bottom of a rafter (which has already been set in position) and the top of a supporting wall plate, and moved laterally along the top of and perpendicular to the supporting wall plate in the direction of the outside face of the supporting stud, until fully contacting both the bottom of the rafter and the top of the supporting wall plate at the preset rafter pitch.
(21) During placement, the rafter is between a vertical leg of the framing member and an adjacent joist/tie such that the framing member vertical leg is flush with a surface of the rafter opposite the adjacent joist/tie and the rafter sits substantially flush on a top surface of the support member horizontal leg or mating surface portion. The framing and support members directly support the rafter vertical load and fasteners driven through the connector into the rafter and adjacent joist/tie member provide a single structural unit with greater lateral stability and the capability to resist and transfer rafter thrust force to the joist/tie member. The width of the support member mating surface portion may vary to accommodate the width of the rafter which is supported by the connector and joist/tie and secured to the framing member. The framing member is then secured to the top of the supporting wall plate and to the rafter and adjacent joist/tie member, respectively, using through-fasteners. The connector may be fabricated to form a single unit, with the support member rotatably secured to the framing member, such as by using a threaded bolt and nut extending through aligned apertures in the support member and framing member, respectively, or by way of a shoulder extending from the support member which is fitted within an associated bushing in the framing member, allowing the support member to freely rotate during placement. The fastener is then tightened when the connector is in proper placement and secured to prevent further rotation.
(22) Fasteners are driven through a plurality of through-holes in the framing member vertical leg, through the rafter and into the adjacent joist/tie. All fasteners used to secure the rafter to the adjacent joist/tie member are placed perpendicular to the framing member vertical leg, which further increases the heel joint connector's load capacity. The framing member is also secured by the craftsman to the supporting wall plate using fasteners driven through a plurality of through-holes in a substantially flat base surface of the framing member. These fasteners provide stability to the connector of the present invention and provide restraint from lateral movement and uplift. Preferably, the framing member, support member, rotatable coupling, and all fasteners have a corrosion-preventing protective coating on their respective surfaces.
(23) Certain terminology is used herein for convenience only and is not to be taken as a limitation of the invention. For example, words such as upper, lower, left, right, horizontal, vertical, upward, downward, clockwise, and counterclockwise merely describe the configuration shown in the drawings. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements.
(24) Additionally, in the subject description, the word exemplary is used to mean serving as an example, instance or illustration. Any aspect or design described herein as exemplary is not necessarily intended to be construed as preferred or advantageous over other aspects or design. Rather, the use of the word exemplary is merely intended to present concepts in a concrete fashion.
(25) Referring now to
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(32) Referring now to
(33) As best seen in
(34) Referring to
(35) In one embodiment, as shown in
(36) Referring again to
(37) As further shown in
(38) The size, placement and spacing of the fasteners is crucial for providing the full intent of the heel joint connector of the present invention, which includes allowing for the rafter thrust force and vertical dead and live load, as well as lateral loads, to be transferred to the adjacent joist/tie member, and provides for restraint against wind uplift. Presently, building codes provide information and tables stating the requirements for fastener size, layout, spacing, edge and end distance for given fastener sizes. It is then left to the craftsman in the field to interpret these requirements for each design loading condition, which leaves open the possibility of craftsman error and results in non-uniformity of positioning and spacing of fasteners and leads to splitting of the rafter, and further effects the required capacity to transfer thrust load.
(39) To avoid this potential problem, advantageously, the self-adjusting heel joint connector of the present invention includes a plurality of through-holes which are pre-sized, pre-positioned and spaced on the framing member vertical leg so that as the connector support member rotates about the swivel joint to self-adjust to the precise preset rafter pitch during placement of the connector, the position of the through-holes (and thereafter, the location of the fasteners) will correspondingly be positioned to be perpendicular to the rafter thrust force (i.e. perpendicular to the grain of the wood) and the tension force in the joist/tie member, to allow for transfer of the thrust force to the adjacent joist/tie member when fasteners are driven therethrough. This results in a time savings in the field and, more so, prevents possible misinterpretation and layout errors by the craftsman.
(40) The framing member of the heel joint connector thus may be used as a guide for the craftsman in the field for proper fastener placement to transfer the rafter thrust force to the joist/tie member, in accordance with building code requirements. As shown in
(41) The size, spacing and position of each through-hole 124 are such that as the rafter pitch varies, the compression and tension forces on the fasteners remain perpendicular to the wood grain in both the rafter and the adjacent joist/tie member and the pre-designed load capacity is achieved. As shown in
(42) As the framing member vertical leg 122 is positioned by the craftsman against the face 201 of the rafter at the precise preset rafter pitch (such as rafter 200 set at any pitch between 4/12 and 12/12, as shown in
(43) This important interface at the heel joint (fastener size, spacing and placement) is often not given the attention that is warranted in the field by the craftsman. This is partly due to the required code interpretation for each case and the actual time required for proper layout of fasteners at each rafter. Having proper fastener size, spacing and layout designated by pre-punched through-holes in the vertical leg of the framing member is a feature unique to the self-adjusting heel joint connector of the present invention, which will prevent possible misinterpretation and layout errors by the craftsman, while allowing for transfer of the thrust force to the adjacent joist/tie member.
(44) As the support member mating surface portion 132 comes into contact with the bottom surface 203 of rafter 200 during placement, the support member 120 rotates about swivel joint or coupling 150 to self-adjust to the precise rafter pitch, enabling the bottom surface 203 of rafter 200 to remain substantially flush with the top surface of support member mating surface 132, while the framing member vertical leg 122 remains flush with the face of rafter 200. Once the connector is properly positioned at the heel joint, the connector framing member may then be secured by the craftsmen to the top surface 221 of the wall plate 220 via the framing member base surface 112 and also to the rafter 200 and adjacent joist/tie member 210 through the framing member vertical leg 122, and the rotatable coupling 150 between framing member vertical leg 122 and support member 120 may be tightened to prevent further rotation of the support member with respect to the framing member, such as by rotating a nut onto a threaded pin or bolt, as shown in
(45) As further shown in
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(48) The connector of the present invention is set in place by hand to its contact surfaces, and, due to the connector's ability to self-adjust to a precise preset rafter pitch, requires no hammering and field metal bending to acquire full surface contact with the bottom of the rafter and top of the supporting wall plate. Moreover, there are no marks needed to be stamped on the connector to provide the selected pitch required: it is self-setting and placed after the rafter has already been set in place by the craftsman to his selected pitch.
(49) The present invention is adaptable to accommodate various sizes of rafters, joist/tie members, wall plates, studs and sheathing, and is not limited to any particular dimensions for these structural components. The self-adjusting heel joint connector is designed to provide a direct load path transfer through each structural member.
(50) Due to its simplicity, size and shape, the connector of the present invention can be readily used with other connectors, such as those used for additional tie-down capacity. The present invention is further adaptable for retrofitting to existing structures and may be used to repair a heel joint of an existing construction.
(51) Thus the present invention achieves one or more of the following advantages. The present invention provides a self-adjusting connector capable of connecting the structural components at a heel joint in a building structure, including a rafter, joist/tie, and top wall plate, in a single connector and without the need for a conventional birdsmouth cut in the rafter. The connector provides for transferring at least minimum code-required surface area between the bottom of a rafter and top of a supporting wall plate, without relying on a skilled craftsman to provide an accurate rafter birdsmouth cut, and eliminates all conventional toe-nailing of the rafter to the supporting wall plate. The connector has no projecting extended sections or protrusions that would interfere with placing adjacent members flush with each other, including joist/tie members or other connectors. The connector is capable of self-adjusting to a precise preset rafter pitch setting for full vertical rafter load transfer, restraint against wind uplift, and lateral loads in each direction, through the connector directly to the top of the supporting wall plate and provides for increased lateral structural stability. The connector further serves as a guide for proper placement of fasteners per code to transfer rafter thrust force to an adjacent joist/tie member.
(52) While the present invention has been particularly described, in conjunction with specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.