Patent Publication Number: US-11384536-B1

Title: Ceiling grid hanger holes

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to improvements in grid tees and in particular to suspension holes for such articles. 
     SUMMARY OF THE INVENTION 
     As disclosed, the location and form of suspension holes, typically in main tees, are arranged to facilitate erection of a grid and in some instances improve its load carrying capacity. As conventional, the suspension holes are located in the vertical, central web extending between an upper reinforcing bulb and a lower panel supporting flange. Holes closest to cross tee slots in the web are horizontally elongated to facilitate threading assembly of hanger wire therethrough, particularly in poorly illuminated conditions. Additionally, the holes are spaced horizontally and vertically away from the cross tee slot than has been customary to enable an installer to more easily finger guide a connector into the slot. Still further, vertical displacement of the hanger holes from the cross tee slots minimizes the risk that a cross tee connector sliding along the main tee during installation will intersect a hanger hole and confuse the installer, thinking the connector is aligned with a cross tee slot or will be obstructed by a hanger wire. Advantageously, the holes are centered one inch above the grid face, eliminating measurements in fractions when establishing the plane of the grid face. 
     The foregoing improvements in the arrangement of the main tee suspension holes can improve the productivity of an installer. This improvement can drive sales ultimately to the manufacturer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a portion of the length of the inventive grid main tee; 
         FIG. 2  is a cross-section of the grid tee of  FIG. 1 ; and 
         FIG. 3  is a diagrammatic plan view of a manual punch tool illustrated in two places. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A main tee or runner  10 , typically supplied in 12 foot lengths, (3,600 mm or industry metric equivalent) is used with cross tees  15  ( FIG. 1 ) to form a suspended ceiling grid. The grid supports rectangular panels, lights, HVAC diffusers and other utilities. As is traditional, the main tees  10  are suspended from superstructure with steel hanger wire, typically 12 gauge. As shown in  FIG. 2 , the tee  10  made of sheet metal has an upper reinforcing bulb  11 , double layer web  12  and lower flange  13  that include a cap strip  14 . 
     The illustrated main tee  10  has cross tee receiving slots  16  conventionally spaced 6 inches (150 mm) apart, along the length of the tee. 
     Situated symmetrically from a cross tee slot  16  are hanger holes  17 ,  18  in the web  12 . Holes  17  adjacent a slot  16  are oblong while outlying holes  18  are round. The width of the holes  17  is preferably the same as the diameter of the holes  18  (for instance 0.219 in.; 5.6 mm) and the elevation from the tee face, provided by the cap strip  14 , of both the oblong and round holes  17 ,  18  is the same. 
     Inspection of  FIG. 1  shows that the lowermost edges of both the oblong and round holes  17 ,  18  is above the upper extremity of the cross tee slot  16 . This construction facilitates assembly of the cross tee connectors in the slots  16 . With a hanger wire in either holes  17  or  18 , the risk that a cross tee connector will be obstructed by a hanger wire in any of the adjacent holes  17 ,  18  when the cross tee assembly motion includes a sideways or lateral component such as when a cross tee end is slid over the flange  13  of the main tee  10 . 
     Installers favor using the oblong holes  17 , particularly at low illumination sites since it is easier to thread a hanger wire through it than the round hole  18 , the area of the oblong hole being larger. 
     A hanger wire in an oblong hole  17  can be shifted horizontally in the hole away from the slot  16  with low force. When an installer uses a finger of one hand on the back side of a main tee  10  to guide a cross tee end connector to a slot  16  by instinctive knowledge of the location of the installer&#39;s finger and to feel the connector in the slot, he can displace the hanger wire in the oblong hole  17  for greater finger access to the slot  16 . 
     Referring to  FIG. 3 , a manually operated cross tee slot punch  21  is diagrammatically illustrated. The punch  21  known in the art, operates in a manner analogous to a manual paper punch; when a handle  22  is depressed, a punch having the cross section of the slot  16  is pressed through the main tee web  12 . An indexing arm  23  has a pin  24  that can be located in either a hole  18  or an oblong hole  17 . The oblong hole  17 , with the pin  24  at the end of the hole  17  adjacent the cross slot  16  positions the arm  23  and slot punch  21  at a nominal dimension, preferably an even two inches from the adjacent slot  16 . When the indexing arm pin  24  is located in the round hole  18 , the punch  21  is centered at another nominal even dimension such as three inches. Equivalent even metric dimensions can be, for instance, 5 cm and 8 cm. In the illustrated case, hole  18  is one inch from the far end of the adjacent oblong hole  17 . Offsets between slots of two inches or three inches on both sides of an original factory slot  16  yield popular spacings of 4 and 6 inches for lighting and/or air ducts. The slot punch  21  can be provided with two arms  23  or can be positioned on both sides of a main tee  11  to produce holes  17 ,  18  symmetrically on both sides of a factory slot. 
     It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.