Patent Application
20200318341
The present invention is directed to a mount, which may be embedded in a concrete component, for supporting a ledge. The mount has a plate with keyhole slots therein and a plurality of anchors extending from the back of the plate. The ledge has a back plate with corresponding studs, for engaging the keyhole slots in the mount. Together, the mount and ledge comprise a corbel system, which can support a beam.
Various prior art devices have been developed to connect one precast concrete component to another. For example, a corbel may be supported by a vertical precast concrete component, so that the corbel may in turn support a beam.
Newkirk—U.S. Pat. No. 5,881,519 discloses a housing assembly with concrete panels that are connected together by angle brackets. The brackets may have a plate with support studs, which are embedded in the concrete.
Friend—U.S. Pat. No. 6,494,639 B1 discloses a primary connector for pre-cast structures. Anchors extend backward from a support plate and are embedded in a concrete panel. Keyhole slots in the plate are engaged by studs extending from a second plate, to connect the panel to a concrete floor. The anchors are positioned near the peripheral edges of the support plate.
The Rapid-Lok® Connection Plate System is comprised of a plate having four or more anchors embedded in a precast concrete structural wall. The plate has a plurality of keyholes that are engaged by studs extending from the back of a ledge. The anchors extend from the back of the plate in a rectangular arrangement.
A corbel may be employed to support a relatively heavy concrete beam, such as a double tee used for roofs, parking decks and bridge overpasses. The weight of the beam generates various tensile and shear stresses on the mount supporting the ledge, which is embedded in a vertical concrete component. Additionally, the weight of the beam generates torque, which may cause the mount plate to bow outward under the load, for example, if the force is transferred to the interior of the plate by studs extending from the ledge.
A mount for a corbel system is provided having a plate with a plurality of keyhole slots extending through the plate, from front to back. The plate is characterized by a top edge, bottom edge and first and second side edges. A plurality of anchors extend from the back of the plate. Each anchor has one end attached to the back of the plate and an opposite end extending away from the back of the plate. The anchors may be embedded in a concrete component, typically a precast concrete component for use as a vertical support in a structure, with the plate parallel to the face of the concrete component. Each of the anchors may be provided with a “foot” or other structure designed to increase its pull-out strength, that is, the force required to pull the anchor from the concrete after the concrete sets, and a rod, extending between the anchor's point of attachment to the back plate and the foot. The rod may be provided with projections along its length to improve pull-out strength. By way of example, headed rebar may be used as the anchor.
Four peripheral anchors are provided, and the point of attachment of each anchor to the back of the plate represents a vertex. Taken together, the four vertices define a convex quadrilateral, that is, a four sided polygon having interior angles that are less than 180° and whose diagonals lie inside of the quadrilateral. Additionally, a fifth anchor is provided and the point of attachment of the fifth anchor to the back of the plate is positioned within a perimeter of the convex quadrilateral defined by the vertices of the four anchors. The addition of the fifth anchor was found to increase the maximum load of the corbel system, i.e. the mount and ledge combination, by over 45%.
The keyhole slots may be characterized as having an entry hole, that is, the relatively wide end through which the head of a stud passes, and a narrow end, that is, the terminus in the slot where the shaft of the stud is seated. As used herein, the location or position of a keyhole in a plate is the center of the shaft of a stud, when the shaft is seated in the narrow end of the keyhole.
In one embodiment of the invention, first and second keyhole slots are positioned within the perimeter of the convex quadrilateral defined by the four peripheral anchors. The point of attachment of the fifth anchor may be positioned laterally between the first and second keyholes. As used herein, the term positioned laterally between keyholes means that the one keyhole is closer to one side edge of the plate than the point of attachment of the fifth anchor and the other keyhole is closer to the opposite side edge of the plate than the point of attachment of the fifth anchor. In another embodiment of the invention, third and fourth keyhole slots are positioned within the perimeter of the convex quadrilateral defined by the four peripheral anchors and the point of attachment of the fifth anchor is laterally positioned between the first and second keyhole slots and the third and fourth keyhole slots.
The convex quadrilateral defined by the four peripheral anchors may be characterized by a vertex centroid. The vertex centroid is the intersection of the line segments connecting the midpoints of the opposite sides of the quadrilateral, that is, the bimedians. In one embodiment of the invention, the point of attachment of the fifth anchor is positioned between the top edge of the plate and the vertex centroid. In another embodiment of the invention, the first and second keyholes are positioned between the top edge of the plate and the vertex centroid.
Also within the scope of the invention is a structure for supporting a beam having the above described mount embedded in an upright concrete component. For example, the concrete component may have a vertical face and the anchors of the mount are cast into the concrete, with the plate of the mount parallel to and flush with the face of the concrete component. A ledge is provided with a back plate and a plurality of studs extending from the back plate. Each of the studs has a shaft, with a head at an end of the shaft opposite the back plate. The end of the shaft opposite the head is attached to the back plate, and for additional support, the shaft may extend through the back plate and protrude from the outer face of the back plate. The studs are attached to the back plate in positions corresponding to the locations of the keyholes in the mount plate. It can be understood that the heads of the studs are inserted in the entry hole of the keyhole and slid downward until the shaft is seated in the narrow end of the keyhole.
The ledge includes a base for supporting the beam, which may be attached to the back plate, for example, at the top edge of the back plate. A gusset extends from the back plate to the base to support the base at the desired angle, typically in a horizontal orientation.
The invention has been described with the mount plate incorporating keyhole slots and the back plate of the ledge incorporating studs, corresponding to the keyhole slots. It can be understood that the invention may also be practiced with the locations of the keyhole slots and studs reversed, that is, (i) the mount plate may be provided with studs extending from its front, and (ii) the back plate of the ledge may be provided with keyhole slots with the entry hole of the slots oriented downward. Furthermore, in the embodiment of the invention first described, which features various relative orientation of the anchors, keyhole slots and mount plate, the word “stud” can be substituted for “keyhole” in the embodiment having studs extending from the mount plate.
Without intending to limit the scope of the invention, the preferred embodiments and features are hereinafter set forth. All of the United States patents and published patent applications cited in the specification are incorporated herein by reference.
Referring to
The four anchors, 9a, 9b, 9c and 9d, define a convex quadrilateral “Q”, having vertices 12a, 12b, 12c and 12d and a perimeter 13. Bimedians 14 and 15 (line segments joining the midpoints of opposite sides of quadrilateral) intersect to define the vertex centroid “VC” of quadrilateral Q. In
A fifth anchor, anchor 16 has a point of attachment 17 to back 4 of plate 2. Point of attachment 17 is located within the perimeter 13 of quadrilateral Q. Anchor 16 is provided with a foot 18, opposite point of attachment 17. In the embodiment of the invention illustrated, point of attachment 17 of anchor 16 is located on bimedian 15. It is believed to be advantageous to counteract the tendency of plate 2 to distort when supporting a ledge to locate point of attachment 17 above bimedian 14, that is, between bimedian 14 and top edge 5.
As shown in
Referring to
Ledge 30 has base 35 attached to back plate 31, for supporting a horizontal beam or other component of a structure. Back plate 31 and base 35 can be a unitary part, such as angle iron. Generally, base 35 and back plate 31 will be at a right angle (90°), but the angle of orientation may vary, as required, for a particular situation. Gusset 36 joins back plate 31 and base 35 for additional support. Gusset 36 may be a single plate attached at a 45° angle between back plate 31 and base 35. Alternatively, base 35 may be supported by multiple gussets connecting base 35 to back plate 31. By way of further example, base 35 may be supported by the rectangular sides of a steel “box”, as is known in the art.
Referring to
The four anchors, 58a, 58b, 58c and 58d, define a convex quadrilateral “Q′”, having vertices 61a, 61b, 61c and 61d and a perimeter 62. Bimedians 63 and 64 (line segments joining the midpoints of opposite sides of quadrilateral) intersect to define the vertex centroid “VC′” of quadrilateral Q′. In
A fifth anchor, anchor 65 has a point of attachment 66 to back 53 of plate 51. Point of attachment 66 is located within the perimeter 62 of quadrilateral Q′. Anchor 65 is provided with a foot 67, opposite point of attachment 66. In the embodiment of the invention illustrated, point of attachment 66 of anchor 65 is located above bimedian 64, that is, between bimedian 64 and top edge 54, to counteract the tendency of plate 51 to distort when supporting a ledge.
Mount 50 is also provided with a six anchor, anchor 68, having a point of attachment 69 to back 53 of plate 51. Point of attachment 69 is located within the perimeter 62 of quadrilateral Q′. Anchor 68 is provided with a foot 70, opposite point of attachment 69. In the embodiment of the invention illustrated, point of attachment 69 of anchor 68 is located above bimedian 64, that is, between bimedian 64 and top edge 54, to counteract the tendency of plate 51 to distort when supporting a ledge.
As shown in
Mount 50 may be embedded in a concrete component, with plate 51 parallel to and substantially flush with a vertical face of the concrete component, as shown in
Referring to
Ledge 80 has base 85 attached to back plate 31, for supporting a horizontal beam or other component of a structure. Base 85 and back plate 31 may be a unitary part, such as angle iron. Generally, base 85 and back plate 81 will be at a right angle (90°), but the angle of orientation may vary, as required, for a particular situation. Gussets 86 and 87 join back plate 81 and base 85 for additional support. Gussets 86 and 87 may be attached at a 45° angle between back plate 81 and base 85.
There are, of course, many alternative embodiments and modifications, which are intended to be included within the following claims.
