Abstract:
A U-shaped frame supporting three bars of circular cross section movable along the arms of the rod, enlarged abutments on the free ends of the rod preventing removal of the bars, and the first bar being attached to a handle so that the bar may be moved up/down the arms by holding/releasing the handle.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/631,249 entitled “SLD (Safety Lowering Device)” filed on 30 Dec. 2011, the contents of which are incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Emergency descent control devices are known. U.S. Pat. No. 6,131,697 teaches a rappelling rope controller which utilizes a U-shaped rod supporting three bars of circular cross section movable along the arms of the rod, and enlarged abutments on the free ends of the rod preventing removal of the bars, but no mechanism for releasing the load are present. US Patent Application No. 2010/0236863 teaches an auto-lock compact rope descent device is a bar with holes for guiding a rope used is descent, and a lever designed to pivot or move relative to the bar and compresses the opening of one of the holes. Compressing the opening increases friction and slows or stops descent. 
     US Patent Application No. 2012/0261212 teaches an anti-panic descender with possibility of ascent that uses a lever. US Patent Application No. 2011/0048852 teaches a descender with fall arrest and controlled rate of descent. US Patent Application No. 2009/0120720 teaches a frictionless descender for abseiling along a rope that also has a handle to control descent. These devices do not show the internal rigging of the rope, and therefore, are not as easy to inspect. Most of these devices provide two loops in a threaded rope, and use a breaking action provided by the lever to slow the movement. 
     SUMMARY OF THE INVENTION 
     The present invention involves a safety lowering device (SLD) that is a descent control device designed specifically to increase the safety and speed of technical rope rescue operations. This device overcomes a number of potential safety concerns with respect to other descent control devices currently available. A primary advantage of the present invention is its ability to automatically lock off the rope thereby stopping unattended descent. This means that if the user, while using the SLD, becomes incapacitated, the device will automatically stop the progress of the lowering operation avoiding potential injury to patients and attendants. Although this is a relatively uncommon occurrence within the technical rescue community, devices passing this so-called whistle test have gained enthusiastic acceptance for their increased levels of safety. 
     A further aspect to this invention is its potential for multifunctional use. Besides its use for the lowering of rescue loads up to about six hundred pounds (600 lbs.), the SLD can easily and almost instantly be converted to function as a simple-to-operate rescue belay device. In the event that the belay function becomes locked-up during use, this device can quickly be converted to the lowering function after remedying the issue that caused the lock-up. This aspect will allow users of two rope systems, for belay and lower, to use one device for both functions simplifying training and reducing the risk of skill retention issues when using different devices. 
     In a primary embodiment of this invention, the rope may be pre-rigged by receiving the rescue rope through the device. In this configuration, the rope cannot become detached from the device unless the rope is physically pulled through the device during its use. To eliminate this possibility, stopper knots are tied on the ends of the rope. This is done prior to the rescue event and is known as pre-rigging, a practice that eliminates potential errors in the heat of a rescue as well as accelerating the rigging process during the rescue event. 
     Another important aspect of this invention is that all components are completely visible without any disassembly which in turns allows a complete inspection to determine if the device has undergone any wear or damage that might compromise its safety. 
     A further advantage of the present safety device is its ability to compensate for shock loads potentially encountered in rescue scenarios. Almost all other descent control devices when locked off do not have the ability to allow limited slippage of the rope through the loaded device. If a device that does not allow limited slippage under load is suddenly shock loaded the majority of this potentially large force must be dissipated in the rest of the system with the potential of over-stressing a component and leading to a possible catastrophic failure. 
     In scenarios where more than one individual will require lowering, it is important to be able to resent the system quickly and safely. High rise rescues during fire events have multiple rescuers using single lines. 
     These and other aspects of the present invention will become readily apparent upon further review of the following drawings and specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the described embodiments are specifically set forth in the appended claims; however, embodiments relating to the structure and process of making the present invention, may best be understood with reference to the following description and accompanying drawings. The drawings, which are not drawn to scale, are for illustration of design principles and parts. 
         FIG. 1  is a side view of an unrigged embodiment of the present invention. 
         FIG. 2  is a top view of an unrigged embodiment of the present invention depicted in  FIG. 1 . 
         FIG. 3  is a side view of an embodiment of the present invention rigged (with a rope threaded through) depicted in  FIGS. 1 and 2 . 
         FIGS. 4A and 4B  are side views of alternative embodiments of the present invention with alternative handle mechanisms as shown from the same position as  FIG. 3 . 
         FIGS. 5A through 5C  are alternative views of the prior art device. 
         FIGS. 6A and 6B  are side and top views respectively of an embodiment of the present invention with handle and plate removed. 
         FIG. 7  is a top view of an embodiment of the present design with the handle and plate removed. 
         FIG. 8  is a side view of a threaded embodiment of the present design with the handle and plate removed. 
         FIGS. 9A through 9C  are side and top views of a handle and plate attachments. 
         FIGS. 10  A and  10 B are side views of an elongated, or telescoping, handle according to an embodiment of the present design. 
         FIGS. 11A and 11B  are elevated environmental views of an alternative embodiment of the present design demonstrating the functionality thereof. 
         FIG. 12  is a cutaway top view of a releasable attachment for a handle and plate assembly according to an alternative embodiment of the present design. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1 and 2  show the safety lowering device  12  in both side and top views prior to being rigged. The safety device  12  is primarily composed of a U frame  14  upon which is affixed three (3) movable bars  16 ,  18 , and  20  which are free to slide along the U frame  14  and held in place by two (2) abutments  22 , e.g. locknuts attached to the ends of the U frame  14 . A shoulder retainer  24 , e.g., screw, is affixed between parallel arms  26  of the U frame  14  which serves as an anchor point for unloader components. The shoulder retainer  24  may be attached to a block  28  affixed between the arms  26 , as shown. 
     To use the safety device  12  as an effective rescue belay device the unloader components can be detached by removing the shoulder retainer  24 , e.g., screw, and swinging a bar clip  28  off of the third bar  20 . Although the present invention is described using a U frame  14 , the frame  14  of the present invention may instead be made of components having two parallel arms and a closed end  32  which may be attached to an anchor, have a rope R threaded through it, or the like. 
       FIG. 3  is a side view of a rigged version of the present invention shown in  FIGS. 1 and 2 . The rope R, which has two ends (or sides) and a length, is threaded between the bars  16 ,  18 , and  19  as shown, and a load (not shown) is suspended from one end (or along one side) of the rope with the load end of the rope R being depicted with an L and the slack end (side) being depicted with an S. If a load L is applied to the rope R, then the bars  16 ,  18 , and  20  are pulled in a direction that effectively traps the rope R between the bars  16 ,  18 , and  20  thereby applying a strong breaking action on the rope R directly proportionally to force exerted by the load. 
     To allow rope to be played out of the device  12 , it should be apparent that the bars  16 ,  18 , and  20  will need to be separated when the device is loaded. This is accomplished by means of the unloader components of the safety device  12  which in turn supplies a mechanical advantage to separate the bars when the lowering lever  30  is moved towards abutments  22 . Depending on the amount of movement of the lever  30 , friction is reduced, and the rope R under load is let out with full control. Releasing the lowering lever  30 , automatically allows the bars  16 ,  18 , and  20  to move back together thus trapping the rope R between them and stopping the descent. 
     Further embodiments of the present design are depicted in  FIGS. 4A and 4B . Variations of the configuration of components employed for the lowering function (unloading). This allows the lowering function to be altered during manufacture depending on whether moving the lowering ever in one direction of the other better suits a particular rescue protocol. 
       FIGS. 5A through 5C  shows a prior art device, U.S. Pat. No. 6,131,697, the contents of which are incorporated herein in their entirety, which utilizes a similar configuration. As a reference to the configuration, and although rigged differently, demonstrates the principle of the bars squeezing the rope thereby creating friction when the device is loaded. 
       FIG. 6A  shows the safety lowering device  12  reeved to function as a rescue belay device. Removal of the unloader components is required for this conversion. should the rescue requirements demand that the device be used to lower the rescue load, the unloader components can be reattached very quickly.  FIG. 6B  shows an alternative embodiment of the present design, in which the basic safety lowering device  12  U frame  14  replaced with two (2) rods with welded eyes formed on their ends.  FIG. 6B  has an alternative form of the U Frame  14  in which the two (2) rods with welded eyes have a middle bar  18  which swings open to allow attachment in the middle of the rope. The unloading components are not shown in  FIGS. 6A and 6B . 
     This embodiment will allow the device  12  to be installed in the middle of a rescue rope R without needing to thread the rope from its end through the device. The anchor point  32  for the unloader components would be attached to one of these frame  14  elements to allow them to rotate independently from one another allowing midline attachment. It should also be noted that the middle bar  18  will not only be easily slidable but also be able to swing away from the frame to allow midline attachment. Further regarding  FIGS. 6A and 6B , the functioning of the middle bar  18  which has a notch disposed to accommodate one arm of the frame  14  and an opening through to accommodate the other arm of the frame  14 . The middle bar  18  swings out to accommodate a rope R and then held by force in place as shown in  FIG. 6A . 
       FIGS. 7 and 8  show a basic prerigged version of the present invention, which will not allow the rope R to become separated from the device. In this embodiment of the present design, the bars do not open but slide along the frame. To reeve this device, the rope R must be threaded between the bars as shown in  FIG. 8 . It is recommended that a crimped eye or sewn eye be used on the load end of the rope to avoid any issues with tied knots. Since the rope travels at right angles to the bars, rope hockling is eliminated. when rigged as in  FIG. 8 , this device is a very effective belay device capable of arresting 600 pounds dropped loads without undue stress to the anchor systems. The anchor or other equipment is attached at the closed end of the U Frame  14  at  32 . When couple with the unloader, it functions as an easily controlled lowering device with the added function of automatically stopping descent of the load when unattended or released. 
       FIGS. 9A through 9C  show greater detail depicting the simplest handle  30  in  FIG. 9A , and two bars in  FIGS. 9B and 9C . The handle  30  has a first end  40  with openings or axles therethrough as shown to accommodate limited rotation thereabout during operation of the unloading.  FIGS. 9B and 9C  show the openings through the bars with a wider bar  36  and a narrower bar  38 . The wider bar  36  may be used as the third bar  16  and/or the first bar  20 , with the narrower bar  38  used as the second (middle) bar  18 . 
     In the embodiment depicted in  FIG. 6B , one of the openings through the narrower bar  38  has been cut out through the side as shown in  FIG. 6B , and discussed hereinbefore. The dimensions of the wider bar  36  in a prototype embodiment are 2.5 inches by 1.05 inches with the two openings accommodating ¾inch pipe and 0.779 inches between the openings. In the narrower bar  38  in a prototype embodiment are two inches by 1.05 inches with the two same two openings as the wider bar  36 . 
     The simplest handle  30  (or handle base) has a second end  42  that may additionally have a grip  48  (not shown in  FIG. 9A ) or a telescoping part with a slot  44 , shown in  FIGS. 10A and 10B , disposed thereon. The handle  30  of a prototype embodiment has a dimension of 10.25 inches long with a ¼inch diameter, while the handle base  30  for the telescoping handle. There is a 35 degree bend at the first end  40 . With the telescoping handle, the handle base  30  is 7.24 inches long in another prototype embodiment. Stainless steel (304) was used. 
     Further regarding the telescoping handle  30  of  FIGS. 10A and 10B , the slide handle part has a round nose spring plunger  46  threads into bent half of handle and holds the handle in position from pressure applied by the ball nose element to the inside of the sliding section. In the prototype embodiment, the sliding section would be rotated ninety degrees from that shown in the figures placing the slot on the bottom of the handle for maximum strength. The sliding section from 20 millimeter diameter aluminum. 
       FIGS. 11A and 11B  are perspective views demonstrating the release, or lowering, position in  FIG. 11A , and the belay position in  FIG. 11B  with the handle  30  being released. The handle must be held in the position shown if  FIG. 11A  with the handle  30  away from the anchor  32 . In  FIG. 11B , the handle  30 , which is released, is up or forward towards the anchor  32 . As can be seen from the perspective views of  FIGS. 11A and 11B , the present does not lay as flat as shown in some of the other figures. 
     Also as shown in greater detail in the partial perspective view of  FIG. 12 , the bar clip  28  and third bar  20  may be configured to mate as shown for quick release. The bar clip  28  seen from the side in  FIGS. 11A and 11B  simply slides over the adjacent bar  20 . Note the shape of the bar  20  has been modified to provide a slot or section out to accommodate the bar clip  28  as shown. This embodiment allows the user to remove the bar clip  28  from the adjacent bar  20 , and then the remaining part of the unloading mechanism may be removed by removing the axle  58  from the opening  50 . Otherwise, these features may be present for manufacturing but affixed with a nonremovable pin for an axle  58 . 
     Should the user alternatively want a dual function, this shoulder retainer may be replaced by a ball lock pin  52  to allow for fast conversions from belay to lower and back again, if required. The ball lock pin  52  shown is attached via a cord  54 . The ball lock pin  52  is provided at the axle or opening  50  which attaches the handle  30  to the frame  14  in a manner such that the attachment may rotate about the axle at  58  (when the pin  52  is in the opening  50 ). The brace  34  extends from the axle at  58  to the handle  30  where another opening with pin or axle at  56  is provided. The handle  30  in this embodiment is rotatably attached to the bar clip  28  at that axle  60  disposed on one side thereof as shown.  FIG. 4A  shows the brace  34  being attached to the axles  56  and  60  to provide an alternative angling to the handle  30  to alternative release or belay positions. Additionally, the end bar  16  may have pens, openings, hooks to accommodate accessories or additional functionality at  44 . 
     A pre-rigged prototype safety lowering device and system is an ultra safe lowering device for use in rope rescue. Constructed of high strength metals, primarily stainless steel, it is designed for years of trouble free operation in urban fire and rescue environments. Initially conceived for single rope rescue from the roofs of tall buildings, the safety lowering device can be used to lower up to six hundred pounds in an easy and secure fashion on 12 to 15 millimeter static kern-mantle and laid rescue rope as well as heat resisting aramid fiber ropes. In the pre-rigged prototype the middle bar  18  cannot be rotated out and therefore the device must be pre-rigged from the end of the rope R preventing any possibility of the device  12  coming separated from the rope R during use, in bags, or in shipment. 
     In use, the device  12  should always be inspected for proper rigging and damage before and after use. It is important hat the user be properly trained in the use of this device  12 . When constructing the anchor, proper care should be taken to avoid any obstructions near the device  12  that might interfere with its proper functioning. When loaded the lever  30  will automatically pivot from a parallel orientation (release position) to the frame to a near right angle orientation (belay position) in the embodiments depicted in  FIGS. 1-3 ,  4 B,  11 A, and  11 B. Lowering the load is accomplished by moving the lever  30  away from the anchor and towards the load. To increase control when lowering a two person load, bring the slack end of the rope up between the abutment nuts  22 , and feed rope R with one hand while operating the lever  30  with the other hand. This increases control by adding friction. 
     At any point while the system is loaded, if the operator lets go of the lever  30 , rope movement through the device will be safely and automatically arrested. After the completion of the lower, the unloaded rope can easily be pulled back through the device by holding the lever parallel to the frame, spreading the break bars  16 ,  18 ,  20 , while a second rescuer pulls the rope through the device from the slack end of the rope. this resents the system for the next lower, if the loaded system is to be unattended take a half hitch on a bight from the slack side and clip it to the load side effectively applying a hark lock to the system. Should the unloading parts need to be removed, a ⅛ inch hex wrench and ⅜ inch open end wrench are required to remove stainless steel shoulder bolt. The handle grip  48  may be a conventional grip, or a ball grip  48 . The grip  48  may be replaced by an eye bolt (not shown) for remote actuation via a chord. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.