Patent Publication Number: US-9847010-B2

Title: Fall protection harness with damage indicator

Description:
TECHNICAL FIELD 
     The present disclosure relates to fall protection harnesses, and in an embodiment, but not by way of limitation, a fall protection harness with a damage indicator. 
     BACKGROUND 
     Fall protection harnesses are critical pieces of safety equipment that are integral to preventing accidents on a job site. Fall protection harnesses provide a reliable restraint system worn by a worker that is connected to a fixed anchor point on a supporting structure, such as a building under construction. Fall protection harnesses are designed to arrest a fall of a worker quickly and safely. However, when a fall occurs, the fall protection harness causes a worker to be suspended in the fall protection harness in a potentially dangerous predicament. If there is no ladder or scaffolding for the worker to climb back onto, the worker will remain suspended until additional rescue help can be rendered. Being suspended in the fall protection harness for an extended period of time can lead to serious injury or death. Consequently, a rapid response is crucial to the safety of the worker. Also, a fall protection harness can be damaged or compromised when a fall occurs. Such damage should be brought to the attention of the proper person or authority, and the fall protection harness should be inspected and/or retired from use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a damage indicator coupled to a fall protection harness before any damage has occurred to the fall protection harness. 
         FIG. 2  illustrates a damage indicator coupled to a fall protection harness after damage has occurred to the fall protection harness. 
         FIGS. 3A-3F  illustrate features of a damage indicator for a fall protection harness. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, electrical, and optical changes may be made without departing from the scope of the present invention. The following description of example embodiments is, therefore, not to be taken in a limited sense, and the scope of the present invention is defined by the appended claims. 
     An embodiment includes a sensor that is integrated into or attached to a fall protection harness. The sensor is capable of automatically sensing damage to the fall protection harness and/or a fall by a person wearing the fall protection harness. When damage is sensed, the fall protection harness can be examined to determine if it is still fit for further use, and when a fall is detected, a responsible person can be immediately notified of the fall event so that the person in the harness can be assisted. Notifying a responsible person of a fall event reduces the response time for help to arrive and consequently reduces the amount of time the person is suspended in the fall protection harness. 
     In an embodiment, a fall protection harness is constructed of nylon straps. At key locations on the harness, the nylon strap is folded over and attached (e.g., by sewing) onto itself to create a damage or fall indicator. In an embodiment, the damage or fall indicator is a paired optical transmitter and optical receiver embedded by sewing them into the damage or fall indicator. Consequently, for example, when a worker falls from a height, the stitching of the damage or fall indicator breaks, thereby causing a break in the optical coupling between the optical transmitter and the optical receiver. The damage to the fall protection harness can also cause a misalignment of the optical transmitter and/or optical receiver or actual damage to the optical transmitter and/or optical receiver. This break, misalignment, or damage generates a signal that is transmitted to an alarm device. A computer processor or other electronics module is attached to both the optical transmitter and optical receiver of the damage or fall indicator. When the optical coupling between the optical transmitter and the optical receiver is broken, the electronics module senses this break and generates a damage or fall alarm. The damage or fall alarm may consist of visual, acoustic, and radio frequency (RF) signals being emitted by the device that will be detected by persons and equipment in the vicinity. In the case of damage to the fall protection harness that is not caused by a fall, the proper authorities are alerted that the fall protection harness should be inspected. In response to a fall by a person wearing a fall protection harness, rapidly alerting persons in the vicinity of the fall ensures rapid extraction of the fallen worker, thereby minimizing further injury and death. 
       FIG. 1  illustrates a damage or fall indicator coupled to a fall protection harness before any damage has occurred to the fall protection harness, and  FIG. 2  illustrates a damage or fall indicator coupled to a fall protection harness after damage has occurred to the fall protection harness. More specifically,  FIGS. 1 and 2  illustrate a strap  100  of a fall protection harness. The strap is folded over on itself and attached via threading  160  or other means of attachment, thereby forming a first surface  110  and a second opposing surface  120 . An optical transmitter  130  is attached to the first surface  110 , and an optical receiver  140  is attached to the second opposing surface  120 . When there is no damage to the fall protection harness, an optical beam  135  is transmitted by the optical transmitter  130  and received by the optical receiver  140 . The optical transmitter  130  and the optical receiver  140  are coupled to a micro-processing unit  150 . Specifically, the optical transmitter  130  is coupled to port DO of the micro-processing unit  150 , and the optical receiver  140  is coupled to port DI of the micro-processing unit  150 . 
     Upon a fall or other damage event to the fall protection harness, the threading  160  breaks, and the first surface  110  and the second surface  120  separate from each other, thereby also causing the optical coupling between the optical transmitter  130  and the optical receiver  140  to be broken or misaligned.  FIG. 2  illustrates such a situation wherein the optical beam  135  is transmitted by the optical transmitter  130  such that it will not be sensed by the optical receiver  140 . After the break or misalignment in the optical coupling between the optical transmitter  130  and the optical receiver  140 , the MPU  150  senses 0 volts at the DI port. When the optical coupling between the optical transmitter  130  and the optical receiver  140  is not broken, approximately half of a volt is sensed at port DO. The condition of the optical transmitter  130  and the optical receiver  140  inside the folded over damage or fall indicator signals the MPU  150  whether damage or a fall has occurred. Once a damage or fall condition is confirmed by the MPU  150 , the MPU  150  signals an alarm mechanism to illuminate a visual alarm, sound an acoustic alarm, and/or transmit RF alarm signals. 
       FIGS. 3A-3F  are a block diagram illustrating operations and features of a damage or fall indicator for a fall protection harness.  FIGS. 3A-3F  include a number of blocks  310 - 381 . Though arranged substantially serially in the example of  FIGS. 3A-3F , other examples may reorder the blocks, omit one or more blocks, and/or execute two or more blocks in parallel using multiple processors or a single processor organized as two or more virtual machines or sub-processors. Moreover, still other examples can implement the blocks as one or more specific interconnected hardware or integrated circuit modules with related control and data signals communicated between and through the modules. Thus, any process flow is applicable to software, firmware, hardware, and hybrid implementations. 
     Referring to  FIGS. 3A-3F , at  310 , a break or misalignment in an optical coupling between an optical transmitter and an optical receiver that are attached to a fall protection harness is sensed. As noted above, actual damage to the optical transmitter or optical receiver can also be sensed. At  320 , it is determined that the fall protection harness is damaged based on the break or misalignment in the optical coupling between the optical transmitter and the optical receiver. At  330 , a signal is generated that indicates that the fall protection harness has been damaged. 
     Block  340  indicates that the damage is caused by a fall by a person wearing the fall protection harness. 
     At  350 , the break in the optical coupling between the optical transmitter and the optical receiver includes physical damage to the optical transmitter or optical receiver, a misalignment of an optical beam between the optical transmitter and the optical receiver, and/or an increased or decreased distance between the optical transmitter and optical receiver. Any of these conditions can be sensed and can indicate damage to the fall protection harness. 
     Block  360  indicates that the fall protection harness includes a strap. The strap is folded over on itself into a folded over area, and the optical transmitter and the optical receiver are attached to the strap at the folded over area. Block  361  illustrates that the folded over area includes a first surface area of the strap that is folded over on and in contact with a second surface area of the strap. As noted above, this first surface area and second surface area can be secured to each other by threaded stitching or other similar means. Block  362  shows that the optical transmitter is coupled to the first surface area and the optical receiver is coupled to the second surface area. Block  363  discloses that upon a fall by a person wearing the fall protection harness, the first surface area separates from the second surface area, thereby breaking (or misaligning) the optical coupling between the optical transmitter and the optical receiver. At  364 , the break in coupling between the optical transmitter and the optical receiver is sensed, and a signal indicating the fall is generated. 
     At  370 , a radio frequency signal causes one or more of a visual alarm to be illuminated and acoustic alarm to be sounded based upon the sensing of damage to the fall protection harness. 
     At  380 , a voltage level within a threshold of variation of voltage is sensed when the optical transmitter and the optical receiver are optically coupled. The sensing of the voltage level within the threshold of variation indicates that no fall has occurred. At  381 , a voltage level beyond a threshold of variation voltage level is sensed when the optical transmitter and optical receiver are not optically coupled. The sensing of the voltage level beyond the threshold of variation indicates that a fall has occurred. As noted above, when a fall has occurred, appropriate personnel can be dispatched to aid the fallen person, and the fall protection harness can be examined for damaged and/or immediately retired from use. 
     It should be understood that there exist implementations of other variations and modifications of the invention and its various aspects, as may be readily apparent, for example, to those of ordinary skill in the art, and that the invention is not limited by specific embodiments described herein. Features and embodiments described above may be combined with each other in different combinations. It is therefore contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the present invention. 
     The Abstract is provided to comply with 37 C.F.R. §1.72(b) and will allow the reader to quickly ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 
     In the foregoing description of the embodiments, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting that the claimed embodiments have more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Description of the Embodiments, with each claim standing on its own as a separate example embodiment.