Abstract:
A concealable cantilever support has a first leg extending from an outward end to an inward end, and near its inward end at least one adjusting hole; and a second leg orthogonal to the first leg, and integrally joined at an inward end thereof to the inward end of the first leg, inward faces of the first and second legs facing each other without intervening material. A portion of the first leg distal from the adjusting hole is restrained flat to the hidden face of the wall, the second leg protrudes from a roomward face of the wall with its outward face upward and orthogonal to the wall, a portion of the first leg adjacent the adjusting hole is free to flex away from the hidden face of the wall by actuation of an adjusting screw inserted through the adjusting hole.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a non-provisional of, and claims priority under 35 USC §119(e) to, U.S. Pat. App. 61/819,723, “LOW PROFILE ADJUSTABLE LIFT BRACKET,” filed May 6, 2013. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention relates to concealable brackets for supporting cantilevered overhangs of heavy counters or shelves. 
     2. Discussion of Art 
     In many kitchens, overhanging (cantilevered) countertops are desired to allow room for a person to sit with their knees under the countertop. Guidelines for installing granite countertops suggest that an overhang more than eight inches should have additional support to prevent the countertop from cracking and to prevent a cracked countertop causing bodily harm. In many cases, the support is desired to be invisible and unobtrusive so that a seated person, or a small child who chooses to walk or sit under the countertop, will not be injured by bumping into the support. It is also important that the support has sufficient contact with the overhang during installation and over the life of the kitchen to prevent the overhang cracking. 
     Current bracket designs consist of a material (usually wood or steel) that has a 90 deg angle and are mounted under the overhang. Brackets are either fastened to the visible surface of the wall or cabinet that supports the countertop overhang or consist of a flat piece of steel that is mounted to the top of cabinet. If a bracket is not firmly attached to the underside of the granite or the granite and/or cabinet shifts or deforms during use, it can still crack. 
     Exemplary conventional brackets include a two piece adjustable bracket, marketed by Brock International, as well as another two-piece adjustable bracket invented by Makainai (U.S. Pat. No. 5,076,648). However, these brackets protrude downward from the undersurface of a supported counter, into the knee- or head-space of a seated adult or a walking child. Thus, these conventional brackets fail to mitigate a known problem of potential bumps. Another known bracket is Tayar&#39;s track-mounted cantilever bracket (U.S. Pat. No. 5,695,163), which averts a risk of knee-bumps only by means of a highly visible track protruding from the wall. 
       FIG. 1  shows in cross-section a conventional standard bracket design  15  supporting an overhang  20  cantilevered from a wall  10 . The typical bracket  15  is fabricated with a 90 degree angle and is mounted to a roomward surface of the wall  10  using several fasteners  30 . The bracket  15  supports the weight of the overhang  20  with a compression strut  16 , or alternatively the bracket may include a solid brace that fills the area  17  defined by the strut  16  (in which case, if made of wood, the bracket may be referred to as a “corbel”). 
     It is known that in order to properly support the weight of the overhang  20 , the fasteners  30  need to be tightened and the strut  16  needs to be sufficiently sturdy such that the bracket  15  and overhang  20  are in contact with each other and extend together in parallel from the wall  10 . However, the bracket  15  necessarily deflects under the load of the overhang, which cannot be ascertained at the time the bracket is manufactured. Therefore, in many installations shims may be required at the end of bracket  15  to ensure the overhang  20  remains horizontal, or the bracket  15  needs to be adjusted vertically along the wall  10  to ensure contact with overhang  20  by changing the fastener locations. This process of aligning the bracket to the wall and overhang can take several iterations. Although the conventional bracket  15  is functional, however all the mounting features are visible and the strut  16  and material  17  can be bumped into by small children or by a seated person&#39;s knee. 
     SUMMARY OF THE DISCLOSURE 
     Generally, embodiments of the invention provide a bracket that has minimal visibility and does not protrude into knee-space, and that has an adjustable feature that allows the installer to preload a supported body at the desired level depending upon the length of overhang, weight of countertop, and the spacing of the brackets. The adjustable feature also ensures contact with the countertop for proper support and safety to prevent bodily harm. 
     Embodiments of the invention provide concealable cantilever supports that have a fine tunable adjustment feature to provide the necessary support for an overhang. In particular, an adjustable upward lift feature provides the flexibility to tailor the bracket force that exerted upward at each contact location depending upon the weight it is supporting and the amount of overhang that is required. The bracket is mounted in such a way to minimize the visibility of the bracket in applications where it is desired not to see the support. A specific application for this bracket is to support the overhang weight of heavy counter-tops (such as granite, quartz, etc.) while not having the bracket visible or intrusive to the region directly under the counter-top. While this is one application example, the bracket can also be used to provide support for any type of overhang where low visibility and adjustable support is desired. 
     A concealable cantilever support, according to embodiments of the invention, is mounted to the inside surface of a wall or cabinet and an adjustment lift feature is then engaged to precisely set a pre-load to match the weight of an overhang that the bracket will supporting. The bracket can be mounted to any wall that has access from the non-visible side or can be installed into factory made cabinets by simply notching the top surface of the cabinet wall and attaching the bracket directly to the inside of the wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a cross-sectional view of a conventional bracket design. 
         FIG. 2  shows in perspective view a low profile adjustable lift bracket according to an embodiment of the invention. 
         FIG. 3  shows in cross-section how a low profile adjustable lift bracket is mounted to a wall according to an embodiment of the invention. 
         FIG. 4  shows in cross-section key dimensions of the low profile adjustable lift bracket shown in  FIG. 3 . 
         FIG. 5  shows in cross-section steps for an adjustment of the lift bracket shown in  FIGS. 3-4 . 
         FIG. 6  shows in perspective a low profile adjustable lift bracket integrally attached to a cabinet wall, according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  shows in side section view a low profile adjustable lift bracket  100  supporting a cantilevered load  20  (e.g., a counter overhang or shelf) on a wall  10 , according to an embodiment of the invention. The lift bracket  100  is mounted to the wall by fasteners  30 , and includes one or more set screws  50  for adjusting a preload of the bracket as further discussed below. 
       FIG. 3  shows in perspective view the Low Profile Adjustable Lift Bracket  100 , next to the support wall  10 . The bracket  100  has a first leg of height H, a second leg of length L, a width W and a thickness T. The thickness T is a function of the material that is used for the bracket and of the overhang  20  weight supported along the length L. 
     Preferably, the inventive bracket  100  is fabricated from sheet steel for supporting granite countertops that weigh about 100 kilograms per square meter (20 pounds per square inch). The thickness T is nominally 4.8 millimeters (0.1875 inches) for a 0.3 meter (1 foot) overhang. The length L ideal for this overhang is 0.3 meters (1 foot), assuming the wall  10  has a thickness X of 101.6 millimeters (4 inches). The bracket length L should be adjusted smaller or larger than 0.3 meters by the same amount that the wall thickness X is smaller or larger than 101.6 millimeters. Additional bracket length L and bracket thickness T is required if the overhang  20  exceeds 0.5 meters (1.7 feet). The bracket height H should be approximately 0.3 meters (1 foot) and the bracket width W should be about 50 millimeters (2 inches) for all countertop overhang applications. Knowing these bracket dimensions, a notch  22  is cut into a horizontal member of the wall  10 , e.g., a top plate or a header. The notch  22  has a width W+(0.125 inches) and depth T+(0.0625 inches) greater than those of the bracket  100 . The additional width and depth of the notch  22  are important to ensure that there is some room in the W direction to adjust the bracket, and that the bracket supports the overhang at the end of the bracket as further discussed below. 
     According to embodiments of the invention, the exemplary bracket  100  is mounted to the wall  10  with the inward surface of the bracket&#39;s first leg contacting a hidden surface of the wall. An outward portion of the bracket&#39;s first leg is fixed flat against the concealed surface of the wall, while an inward portion of the first leg (nearer to the joint of the first and second legs) is free to flex away from the wall. Meanwhile, the outward end of the bracket&#39;s second leg extends through the notch  22  to project beyond a roomward surface of the wall. For example, as shown in  FIG. 3 , the exemplary bracket  100  includes within a lower or outward portion of its vertical first leg a hole  70 , which preferably has a hole size of at least 9.5 millimeters (0.37 inches). The hole  70  is disposed at least about 25 millimeters (1 inch) from the end of the bracket  100 . Between the hole  70  and the corner formed between the first and second legs of the bracket  100 , at least two additional holes  60  are drilled with hole sizes of at least about 9.5 millimeters (0.37 inches), spaced approximately every 25 millimeters (1 inch) along the middle segment of bracket height H. Both the hole  70  and the holes  60  can be countersunk so that wood screws  30 , to be inserted through the holes, will be flush with the bracket surface visible in  FIG. 2 . Additionally, about 12 millimeters (0.5 inches) below the inside surface of the horizontal or second leg of the bracket  100  (see dimension A in  FIG. 4 ), two holes  50  are drilled and tapped with M-8 threading. The holes  50  are located approximately 25 millimeters (1 inch) apart for accepting set screws  52  each having a length of at least about 13 millimeters (0.5 inches) and preferably no more than 30 millimeters (1.2 inches). 
     Thus, threaded fasteners provide one mode for attaching the bracket  100  to the wall  10 . Another option is to use construction adhesive for attaching the bracket to the wall. Another option is to clamp the bracket to the wall using either metal clamping plates, or a wooden clamp bar. Yet another option could be use of wood rivets. All these options presume the cabinet wall is built of wood; however, cabinets also can be constructed of metal or plastic, and in such cabinetry (as shown in  FIG. 6 ), welding, friction welding, or integral forming may be viable alternative modes of attaching the bracket  100  to the wall  10 . In any embodiment, it is important that the inward portion of the first leg (including the corner formed by the first leg and the second leg, and the adjusting hole(s)  50 ), should be free along a length G ( FIGS. 4 and 6 ) to deflect away from the concealed surface of the wall according to adjustment of the adjusting screw(s)  52 . 
     The exemplary embodiment presumes that the adjusting holes  50  per se provide threaded means for adjustably receiving the adjusting screws  52 . However, in another arrangement, the adjusting holes may be plain clearance holes and the inward surface of the first leg may be indented at the adjusting holes to capture or hold discrete threaded means (e.g., nuts) for adjustably receiving the adjusting screw. 
     For example,  FIG. 4  shows a detailed cross section of the concealable cantilever support  100 . The bracket is secured to the wall  10  (see  FIG. 2 ) with a first fastener  30  in hole  70  and a second fastener  30  in one of the four holes  60 . The inward segment of the first leg, above the second fastener, has a length G. The nominal placement of the second fastener is to have dimensions G and K equal. The second fastener can also be placed in locations that make G not equal to K, if there is an obstruction at the location where G=K or if the bracket thickness is larger or smaller than the nominal thickness recommended. The bracket  100  may be secured to a vertical stud of the wall, or to an adequately-braced cripple or header. 
       FIG. 5  shows a sequence of cross-sections to explain how the adjustable lift feature is set properly to support overhang  20 . The left cross section shows the Concealable cantilever support  100  attached to wall  10  using two fasteners  30  such that the bracket fits into notch  22  and is about 0.0625 inches from the top of wall  10 . The center cross-section shows what happens when the set screws are evenly engaged to create a gap M, thereby deflecting the height H and causing the length L of the bracket  100  to raise vertically a distance N. Because of the location of the set screw  50  and the bracket length L, small changes to gap M caused by tightening the set screws, allow for a precise control of vertical rise N and the resulting spring force that the bracket applies to the overhang when deflected back to horizontal. There is a direct relationship of the adjustment of set screw  50  to the amount of force required to return N to zero. This relationship is used to properly set the adjustment feature on bracket to provide the proper support for countertop overhang. 
     The amount of weight required to return N to zero represents the amount of pre-load or lift that the adjustable bracket is applying to support overhang  20 . Table 1, below, provides set screw guidelines for a typical counter-top application based upon the bracket design described above, with distance G=135 mm (5.3 inches). 
                                                                                                       TABLE 1                   Number of Set Screw Turns After Bracket End        is Level With Cabinet Top            Counter                Weight       Bracket Length L (inches)            (lb/sq ft)   Counter Material   6   8   10   12   14   16                    18   Granite 1¼″ thick   2   2.5   3   3.5   4   4.5       12   Granite ¾″ thick   1.3   1.7   2   2.3   2.7   3       6   Resin composite   0.7   0.8   1   1.2   1.3   1.5                    
Once the bracket has been attached to the wall, the set screws are adjusted so that N=zero. Additional set screw turns are then made following Table 1 based upon a calibration of the upward force for the corresponding set screw rotations.
 
     The wall  10  may require reinforcement depending on its original thickness and on the weight of the cantilever load. Standard cabinetry has a typical wall thickness of about 13 mm (½ inch) hardwood. However, a thickness of 19 mm (¾ inch) standard pine is expected adequate to support any load listed in the table above. Thus, if the bracket  100  is installed into an existing wall, then a 2×4 brace fastened between the wall studs by angle brackets should suffice to support the bracket. On the other hand, if the bracket  100  is installed into an existing cabinet with a thickness less than 19 mm (¾ inch), then it is recommended that a ½″ to ¾″ piece of plywood is added to the inside surface that extends from the floor to to top of the cabinet for adequate support of the bracket. Another option is to build “granite ready” cabinetry with a roomward wall or walls of at least 18 mm (¾ inch) thickness, which is greater than the industry standard of about 13 mm (½ inch). “Granite ready” cabinetry also can have at least one roomward wall pre-notched with a series of notches  22  at spacing sufficient to support the heaviest expected counter overhang. For example, notches  22  can be spaced at most about 0.7 m (28 inches) apart, but no closer than 0.3 m (12 inches). More preferably, notches  22  can be spaced at about 0.5 m (20 inches) apart. This latter spacing is considered optimal for standard granite thickness countertop seating overhangs of about 0.3 m (12 inch). 
     As described with specific application to granite countertops, the concealable cantilever support provides features that uniformly support an overhang, directing the weight of the overhang to the top and inner surface of a supporting wall, while hiding the bracket mount and fasteners behind the wall. It should be understood that this bracket could be applied to other applications that require support and hence the method of installation or attachment may differ depending upon the specific need. 
     Although exemplary embodiments of the invention have been described with reference to attached drawings, those skilled in the art will apprehend various changes in form and detail consistent with the scope of the invention as defined by the appended claims.