Patent Publication Number: US-2022220806-A1

Title: Safety Roof Hatch System

Description:
RELATED APPLICATION DATA 
     The present application is a Divisional of U.S. patent application Ser. No. 16/029,347 filed Jul. 6, 2018, which is related to and claims the benefit of commonly-owned and U.S. Provisional Patent Application No. 62/620,557 entitled SAFETY ROOF HATCH SYSTEM, filed on Jan. 23, 2018, which application is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to hatches allowing access to building roofs and, in particular, to a system allowing safer opening and closing of a roof hatch. 
     BACKGROUND ART 
     Most commercial, industrial and institutional buildings have some means of roof access for maintenance of the roof system and any roof mounted equipment. The usual means of roof access is by way of a stairwell which is built beyond the highest story of the building so that the top of the stair opens onto the roof or by means of a ladder or ship&#39;s ladder which leads to a water-tight roof hatch which, when opened, allows the user to climb out through the hatch onto the roof. Roof access ladders are usually steel or aluminum fabrications which meet, to some degree or another, OSHA regulations governing ladder dimensions, attachment, etc. Most roof hatches are hinged on one side and are built with a latching mechanism, which allows the hatch to be locked from the inside by use of a padlock. In addition, most roof hatches have gas shocks (like those on an SUV&#39;s lift gate) to make opening the hatch less difficult. 
       FIGS. 1A and 1B  illustrate two examples of conventional ladder/hatch configurations. In both examples, the top of a fixed ladder  10  ends in or at the bottom of a hatch curb  12 , which provides a frame for the inside of the opening in the roof  14 . A weather-tight hinged hatch lid  16 , when closed, prevents unauthorized access both to and from the roof  14  and prevents wind, rain, and snow from leaking inside. When unlocked and opened, the lid  16  allows authorized personnel to climb onto the roof  14  for inspection or maintenance. 
     The usual configuration of ladder  10  and hatch  16  places the locking handle at the top of the ladder  10  and nearest the person on the ladder  10 . Such a configuration requires that the person opening the hatch  16  be able to hold onto the ladder  10 , find the correct key (usually on a ring holding multiple building keys), get the key into the lock with one hand (or if the person is particularly adept, use two hands by finding a place other than the ladder rungs to put a foot while using both hands on the padlock), remove the padlock, put it in a secure location, and then open the hatch  16 . Anyone performing such a precarious sequence can relate that it is a white-knuckle experience, no matter how often it is done. 
     However, the process is not yet complete. Because the access ladder  10  usually ends within a few inches of the hatch curb  12 , the person on the ladder  10  must climb out by holding the hatch curb  12  and climb further up the ladder  10  until they can get a foot out onto the roof  14 . This usually puts the climber into a doubled over position, similar to one&#39;s posture when touching one&#39;s toes. 
     After completing the task on the roof  14 , it is necessary to reverse the procedure, which starts with holding the top of the curb  12  (about four inches above the roof surface  14 ), getting a foot on the top rung of the ladder  10  to begin the climb back down, and stopping to close and re-lock the hatch  16 . At this point, the gas shocks make closing the hatch  16  more difficult because, while they make opening the hatch  16  easier, they resist closing the hatch  16 . 
     It will be appreciated, therefore, that transitioning from the top of the ladder  10 , over the curb  12 , and onto the surface of the roof  14 , and reversing the process, can be difficult and dangerous, particularly when the ladder is vertical as in  FIG. 1B . 
     A number of devices attempt to solve the problem of making the transition easier and safer. However, they may in fact make getting out of the hatch even more difficult and, therefore, less safe. One such device  20  is illustrated in  FIG. 2A . The device  20  bolts onto the hatch curb  12  and extends above the curb  12 , providing an additional, higher handhold when climbing up onto or down from the roof. Another such device  30  is illustrated in  FIG. 2B . The device  30  is a telescoping post having a lower section  30 A that clamps onto the ladder  10 . When the user is at the top of the ladder  10  and has opened the hatch lid  16 , the user raises the upper section  30 B of the post  30  so that it extends above the curb  12  and locks it in place. The user may then hold on to the upper section  30 B for support as they climb out of the opening, over the curb  12 , and onto the roof  14 . However, even using these and other such devices can make for a precarious transition. 
     SUMMARY OF THE INVENTION 
     A system is provided for safe access to a roof through an opening in a roof of a structure having a fixed ladder leading upward to the opening. The system includes a mechanism to drive a set of pushrods to raise a hatch covering the opening. In one embodiment, the system includes a section of ladder secured to the underside of the hatch. In another embodiment, the system includes an extendable ladder driven by the drive mechanism to slide along the fixed ladder and extend through the opening in the roof when the hatch is raised. In still another embodiment, the system includes a safety pole driven by the drive mechanism to extend through the opening in the roof when the hatch is raised. The system allows someone who needs to access the roof for inspection or maintenance to open the hatch from a safe location, climb up through the opening in the roof, and safely step onto the roof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a conventional ladder/hatch configuration; 
         FIG. 1B  illustrates another conventional ladder/hatch configuration; 
         FIG. 2A  illustrates a prior art ladder extension device; 
         FIG. 2B  illustrates a prior art telescoping support pole; 
         FIG. 3A  is a side view of an embodiment of a roof hatch safety system of the present invention in the hatch closed position; 
         FIG. 3B  is a front view of the system of  FIG. 3A ; 
         FIG. 3C  is a side view of the system of  FIG. 3A  in the hatch open position; 
         FIG. 4A  is a side view of another embodiment of a roof hatch safety system of the present invention in the hatch closed position; 
         FIG. 4B  is a side view of the system of  FIG. 4A  in the hatch open position; 
         FIG. 5A  is a front view of a third embodiment of a roof hatch safety system of the present invention in the hatch closed position; 
         FIG. 5B  is a side view of the system of  FIG. 5A  in the hatch closed position; 
         FIG. 5C  is a side view of the system of  FIG. 5A  in the hatch open position; 
         FIG. 6A  is a front view of a fourth embodiment of a roof hatch safety system of the present invention in the hatch closed position; 
         FIG. 6B  is a side view of the system of  FIG. 6A  in the hatch closed position; 
       and 
         FIG. 6C  is a side view of the system of  FIG. 6A  in the hatch open position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
       FIGS. 3A and 3B  are side and front views, respectively, of an embodiment of the roof hatch safety system  100  of the present invention with the hatch lid in its closed position.  FIG. 3C  is a side view of the system  100  with the hatch lid  16  in its open position. The hatch lid  16  is connected to the hatch curb  12  with one or more hinges  18 . An existing ladder  10  and hatch lid  16  may be retrofitted with the system  100  or the system  100  may be used as part of a new installation. 
     The system  100  includes a section of ladder  102  mounted on the underside of the hatch lid  16  with one end (hereinafter “the lower end”) close to the hinge side of the hatch lid  16 ; the opposite (“upper”) end of the lid-mounted ladder section  102  extends towards the opposite side of the hatch lid  16 . Thus, the ladder section  102  is in a plane substantially parallel to the underside of the lid  10 . The system  100  also includes a pair of upper and lower pushrods  104 A,  104 B, a connecting ladder section  106 , and a drive mechanism  120 , which is secured with a bracket  122  to the fixed ladder  10  or the inside wall behind or next to the fixed ladder  10 . 
     One end (the “upper end”) of each upper pushrod  104 A is secured to the underside of the hatch lid  16  and the opposite end (the “lower end”) of each is connected through a hinge  104 C to one end (the “upper end”) of a corresponding lower pushrod  104 B. As shown in the front view of  FIG. 3B , the opposite end (the “lower end”) of each lower pushrod  104 B is coupled to the drive mechanism  120  through a drive shaft  124 . One end (the “upper end”) of each side of the frame of the connecting ladder section  106  is connected through a hinge to the corresponding sides of the frame of the lower end of the lid-mounted ladder section  102 . The opposite end (the “lower end”) of each side of the frame of the connecting ladder section  106  is shaped like a hook facing the inside wall. When the system  100  and hatch lid  16  are in the closed position, the lower ends of the sides of the connecting ladder section  106  remain free and rest against the outside (relative to the wall) of the drive shaft  124 . 
     When the drive mechanism  120  is operated, the drive shaft  124  rotates and causes the upper and lower pushrods  104 A,  104 B to rise. The pushrods  104 A,  104 B in turn push the hatch lid  16  upward. As the hatch lid  16  rises, the hatch-mounted ladder section  102  rises with it, pulling the upper end of the connecting ladder section  106  with it. When the hatch lid  16  is fully in the open position, the pushrods  104 A,  104 B firmly hold the hatch lid  16  upright and prevent it from closing. In addition, the hooked lower ends of the sides of the connecting ladder section  106  mate with the drive shaft  124  or the upper end of the fixed ladder  10 , thereby connecting the fixed ladder  10  with the hatch-mounted ladder section  102  and forming a continuous ladder from the bottom of the fixed ladder  10  onto the hatch lid  16 . In this way, someone who needs to access the roof for inspection or maintenance, is able to open the hatch lid  16  from a safe position and climb up the fixed ladder  10 , through the opening in the roof  14  onto the connecting ladder section  106  and the hatch-mounted ladder section  102 , and then safely step over the hatch curb  12  onto the roof  14 . 
       FIGS. 4A and 4B  illustrate side views of another embodiment of a roof hatch safety system  200  of the present invention in the hatch closed and open positions, respectively. The system  200  includes a ladder section  202  that is connected at its upper end to the hatch lid  16  with hinges. A pushrod  204  is coupled at its lower end to the drive mechanism  120  and the opposite end is coupled to the hatch-mounted ladder section  202  below the upper end of the hatch-mounted ladder section  202 . When the drive mechanism  120  is activated, the upper end of the pushrod  204  rises, lifting the hatch lid  16  and with it the hatch-mounted ladder section  202 . When the hatch lid  16  is fully open, as in  FIG. 4B , the hatch-mounted ladder section  202  is contiguous with the fixed ladder  10 , forming a continuous ladder from the bottom of the fixed ladder  10  onto the hatch lid  16 . As with the system  100  illustrated in  FIGS. 3A-3C , someone who needs to access the roof for inspection or maintenance, is able to open the hatch lid  16  from a safe position and climb up the fixed ladder  10 , through the opening in the roof  14  onto the hatch-mounted ladder section  202 , and then safely step over the hatch curb  12  onto the roof  14 . 
       FIGS. 5A, 5B, and 5C  illustrate a third embodiment of a roof hatch safety system  300  of the present invention. In the system  300 , the drive mechanism  120  raises and lowers a pushrod  304 , the top section  304 A of which is attached with a hinge or pivot to both the lower section  304 B and the underside of the hatch lid  16  and is also attached to a sliding ladder extension  306 . When the drive mechanism  120  is operated in one direction, the pushrod  304  is raised to open the lid  16 . The ladder extension  306  also rises and extends upward through the opening in the roof ( FIG. 5C ), allowing a user to safely climb up the ladder through the hatch and step onto the roof  14 . When the drive mechanism  120  is operated in the opposite direction, the pushrod  304  retracts the ladder extension  306  and closes the lid  16 . 
       FIGS. 6A, 6B, and 6C  illustrate a fourth embodiment of a roof hatch safety system  400 , similar to the third embodiment  300  but with a safety pole  408  instead of a ladder extension. The drive mechanism  120  raises and lowers a pushrod  404 , to which the safety pole  408  is attached. A top section  404 A of the pushrod  404  is attached with a hinge or pivot to both a lower section  404 B and the underside of the hatch lid  16 . When the drive mechanism  120  is operated in one direction, the pushrod  304  is raised to open the lid  16  ( FIG. 6C ). The connected safety pole  408  also rises and extends through the opening in the roof  14 , allowing a user to safely climb up the ladder through the hatch and step onto the roof  14  while holding onto the pole  408 . When the drive mechanism  120  is operated in the opposite direction, the pushrod  404  retracts the pole  408  and closes the lid  16 . 
     The systems  300  and  400  may be included as part of a new installation or may be retrofitted to an existing installation. 
     In the various embodiments, the drive mechanism  120  may be hand operated, such as with a hand crank. Alternatively, the drive mechanism  120  may include an electric motor. Although the drive mechanism  120  may be operated at the top of the fixed ladder, for safety and convenience it is preferable that it be operated from the bottom of the ladder  10 . When the drive mechanism  120  is operated from the bottom of the fixed ladder  10 , the hand crank or motor may be coupled to the drive mechanism  120  through any appropriate device, such as a drive rod, gear and chain, or the like. Whether located at the hatch lid  16  or the bottom of the ladder  10  and whether hand operated or electrically driven, the drive mechanism  120  is preferably lockable to prevent unauthorized use. 
     The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.