Patent Publication Number: US-2019195310-A1

Title: Force damper

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62/610,786, filed Dec. 27, 2017, which application is incorporated herein by reference. 
    
    
     FIELD 
     The invention broadly relates to a force damper, more specifically to a force damper used as a fall mitigation device, and even more particularly to a force damper used as a fall mitigation device having a single use, collapsible resilient member arranged to prevent reuse of the force damper after arresting a falling object, e.g., a roofing construction worker. 
     BACKGROUND 
     Fall prevention and fall arrest systems are known in the art. For example, one such system includes a stretchable shock absorbing lanyard, e.g., Model No. 1340101 PRO™ Stretch Shock Absorbing Lanyard manufactured by Protecta®. The inner core of the device extends from about four and a half feet to about six feet while absorbing energy of a falling object. Although this device may be suitable in some situations, it cannot ensure safety in situations where the falling height is similar to the height of the object falling, e.g., a worker that is six feet falling off an elevated level of seven feet. However, heretofore, such damper devices were arranged to be reused over and over again. 
     Regulations and/or a desire to ensure worker safety have created a need for force damping systems that cannot be used more than a single time as the integrity of a previously used force damper cannot be verified. For example, a force damper used to slow the fall of a three hundred pound object may not perform effectively while slowing the fall of a three hundred pound object a second time, while the same force damper may perform repeatably when slowing the fall of a one hundred fifty pound object. Thus, there is a long-felt need for a force damper that is easy to operate, inexpensive to build, safe for its intended use and that precludes subsequent uses. 
     SUMMARY 
     The present invention broadly comprises a force damper arranged to progressively arrest a first force imparted by an object moving in a first direction, the force damper including a housing, a driving member and a resilient member. The housing includes a first end and a second end, the first end having a first surface, a second surface opposite the first surface and a first connection point secured to the first surface, and the second end having a through bore and a third surface opposingly disposed relative to the second surface. The driving member includes a first end, a second end and a shaft therebetween, the first end comprises a stop and the second end comprises a second connection point. The resilient member is formed from a material that at least partially undergoes plastic deformation when the first force is arrested. The resilient member is disposed between the stop and the third surface and imparts a second force on the stop toward the second surface. 
     The present invention also broadly comprises a force damper arranged to progressively arrest a first force imparted by an object moving in a first direction, the force damper including a housing, a driving member and first and second resilient members. The housing includes a first end and a second end, the first end having a first surface, a second surface opposite the first surface and a first connection point secured to the first surface, and the second end having a through bore and a third surface opposingly disposed relative to the second surface. The driving member includes a first end, a second end and a shaft therebetween, the first end having a stop and the second end having a second connection point. At least one of the first and second resilient members is formed from a material that at least partially undergoes plastic deformation when the first force is arrested. The first and second resilient members are disposed between the stop and the third surface and impart a second force on the stop toward the second surface. 
     These and other objects and advantages of the present invention will be readily appreciable from the following description of preferred embodiments of the invention and from the accompanying drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
         FIG. 1  is a side cross sectional view of an embodiment of a present force damper; 
         FIG. 2  is a top perspective view of an embodiment of a present force damper; 
         FIG. 3  is a front perspective, a side elevational and a front elevational view of an embodiment of a plate included in some embodiments of a present force damper; 
         FIG. 4  is a front perspective, a side elevational and a front elevational view of an embodiment of a plate included in some embodiments of a present force damper; 
         FIG. 5  is a front perspective, a side elevational and a front elevational view of an embodiment of a plate included in some embodiments of a present force damper; 
         FIG. 6  is a front perspective, a side elevational and a front elevational view of an embodiment of a tube included in some embodiments of a present force damper; 
         FIG. 7  is a front perspective, a side elevational and a front elevational view of an embodiment of a stop included in some embodiments of a present force damper; 
         FIG. 8  is a front perspective, a side elevational and a front elevational view of an embodiment of a tube included in some embodiments of a present force damper; 
         FIG. 9  is a front perspective, a side elevational and a front elevational view of an embodiment of a shaft included in some embodiments of a present force damper; 
         FIG. 10  is a front perspective and a front elevational view of an embodiment of a resilient member included in some embodiments of a present force damper; 
         FIG. 11  is a front perspective view of an embodiment of a connection point included in some embodiments of a present force damper; 
         FIG. 12  is a front perspective view of an embodiment of a connection point included in some embodiments of a present force damper; 
         FIG. 13  is a side cross sectional view of an embodiment of a present force damper; 
         FIG. 14  is a front elevational view of an embodiment of a present force damper; 
         FIG. 15  is a back elevational view of an embodiment of a present force damper; and, 
         FIG. 16  is a top perspective view of an embodiment of a present force damper. 
     
    
    
     DETAILED DESCRIPTION 
     At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects. 
     Furthermore, it is understood that this invention is not limited to the particular methodologies, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. 
     It should be understood that use of “or” in the present application is with respect to a “non-exclusive” arrangement, unless stated otherwise. For example, when saying that “item x is A or B,” it is understood that this can mean one of the following: (1) item x is only one or the other of A and B; (2) item x is both A and B. Alternately stated, the word “or” is not used to define an “exclusive or” arrangement. For example, an “exclusive or” arrangement for the statement “item x is A or B” would require that x can be only one of A and B. Moreover, as used herein, the phrases “comprises at least one of” and “comprising at least one of” in combination with a system or element is intended to mean that the system or element includes one or more of the elements listed after the phrase. For example, a device comprising at least one of: a first element; a second element; and, a third element, is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or, a device comprising a second element and a third element. A similar interpretation is intended when the phrase “used in at least one of:” is used herein. Furthermore, as used herein, “and/or” is intended to mean a grammatical conjunction used to indicate that one or more of the elements or conditions recited may be included or occur. For example, a device comprising a first element, a second element and/or a third element, is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or, a device comprising a second element and a third element. 
     It should be appreciated that the term “substantially” is synonymous with terms such as “nearly,” “very nearly,” “about,” “approximately,” “around,” “bordering on,” “close to,” “essentially,” “in the neighborhood of” “in the vicinity of” etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term “proximate” is synonymous with terms such as “nearby,” “close,” “adjacent,” “neighboring,” “immediate,” “adjoining,” etc., and such terms may be used interchangeably as appearing in the specification and claims. The term “approximately” is intended to mean values within ten percent of the specified value. 
     By “non-rotatably connected” elements, we mean that: the elements are connected so that whenever one of the elements rotate, all the elements rotate; and relative rotation between the elements is not possible. Radial and/or axial movement of non-rotatably connected elements with respect to each other is possible, but not required. Additionally, “plastic deformation” is intended to mean instances when a sufficient load is applied to a material that causes a permanent change in shape to that material. 
     Adverting now to the figures, it should be appreciated that the figures depict various embodiments of the present force damper. The elevated work surface, e.g., roof, the falling object, e.g., a worker, a tool, a container filled with materials, etc., are not shown in the figures. One of ordinary skill in the art will readily appreciate the type, form and arrangement of each of the foregoing structures and therefore depiction in the figures is unnecessary. For the purpose of clarity in the detailed description, these structures are not included in the figures; however, the structures are discussed herebelow. 
     The present invention broadly includes force damper  50  arranged to progressively arrest a first force imparted by an object moving in a first direction, i.e., the direction depicted by arrow  51 . Force damper  50  comprises housing  52 , driving member  54  and resilient member  56 . Housing  52  comprises first end  58  and second end  60 . First end  58  includes first surface  62 , second surface  64  opposite first surface  62  and first connection point  66  secured to first surface  62 . Second end  60  includes through bore  68  and third surface  70  opposingly disposed relative to second surface  64 . Driving member  54  comprises first end  72 , a second end  74  and shaft  76  therebetween. First end  72  comprises stop  78  and second end  74  comprises second connection point  80 . Resilient member  56  is formed from a material that at least partially undergoes plastic deformation when the first force is arrested. Resilient member  56  is disposed between stop  78  and third surface  70 , and imparts a second force on stop  78  toward second surface  64  and on second end  60  toward third surface  70 , as depicted by bi-directional arrow  82 . 
     In some embodiments, housing  52  encloses resilient member  56 . In some embodiments, second end  60  of housing  52  comprises block  84 . Block  84  comprises through bore  68  and third surface  70 . In some of these embodiments, block  84  is formed from a urethane material. Thus, block  84  may provide force damping in addition to that of resilient member  56 . It should be appreciated that block  84  may also be formed from a rigid material, e.g., a metal, and in those embodiments block  84  does not provide additional force damping. 
     In some embodiments, resilient member  56  is a resilient polymer, a leaf spring, a shock absorber, and/or a compression spring, e.g., compression spring  86 . In some of these embodiments, resilient member  56  is compression spring  86 , and in some of these embodiments, compression spring  86  is formed from a chrome silicon steel material. 
     In some embodiments, force damper  50  further comprises securing line  88  selected from the group of: a rope, a cable, and/or a tether, and securing line  88  may in turn be connected to a harness and/or a belt. Subsequently, the object to be secured, e.g., a worker, a tool, a container, etc., is secured directly to the rope, cable and/or tether, or alternatively, secured directly to the harness and/or belt. It should be appreciated that securing line  88  is depicted as a rope only and that the structure and form of a cable and/or a tether are readily apparent to one having ordinary skill in the art and therefore depiction in the figures is unnecessary. Similarly, depiction of a subsequent harness and/or belt is also unnecessary. It should be further appreciated that various types of securing lines are more suitable for the present force damper, e.g., stretchable and/or shock absorbing ropes, as additional force may be damped by these types of securing lines. However, including such types of securing lines is not required. 
     In other embodiments, the present invention broadly includes force damper  100  arranged to progressively arrest a first force imparted by an object moving in a first direction, i.e., the direction depicted by arrow  101 . Force damper  100  comprises housing  102 , driving member  104  and first and second resilient members  106  and  108 , respectively. Housing  102  comprises first end  110  and second end  112 . First end  110  includes first surface  114 , second surface  116  opposite first surface  114  and first connection point  118  secured to first surface  114 . Second end  112  includes through bore  120  and third surface  122  opposingly disposed relative to second surface  116 . Driving member  104  comprises first end  124 , second end  126  and shaft  128  therebetween. First end  124  comprises stop  130  and second end  126  comprises second connection point  132 . At least one of first and second resilient members  106  and  108 , respectively, is formed from a material that at least partially undergoes plastic deformation when the first force is arrested. In other terms, one or both of first and second resilient members  106  and  108 , respectively, undergoes plastic deformation while arresting the first force. Thus, one of the resilient members may be arranged to arrest a portion of the force and display visible, permanent deformation while the other resilient member provides force damping while undergoing only elastic deformation, i.e., temporary shape change with restoration to its original shape after damping is complete. First and second resilient members  106  and  108 , respectively, are disposed between stop  130  and third surface  122 , and impart a second force on stop  130  toward second surface  116  and on second end  112  toward third surface  122 , as depicted by bi-directional arrow  134 . 
     In some embodiments, housing  102  further comprises reinforcement plate  136  arranged between first and second ends  110  and  112 , respectively, of housing  102 . In some embodiments, housing  102  at least partially encloses first and second resilient members  106  and  108 , respectively. It should be appreciated that “partially encloses” is depicted in the figures in that tubes  138  include open portions  140  which permit the linear actuation of stop  130  as force damper  100  arrests the first force imparted by the object moving in the first direction. In some embodiments, second end  112  of housing  102  comprises plate  142 . Plate  142  comprises through bore  120 . In some embodiments, force damper  100  further comprises securing line  144  selected from the group of: a rope, a cable, and/or a tether, and securing line  144  may in turn be connected to a harness and/or a belt. Subsequently, the object to be secured, e.g., a worker, a tool, a container, etc., is secured directly to the rope, cable and/or tether, or alternatively, secured directly to the harness and/or belt. It should be appreciated that securing line  144  is depicted as a rope only and that the structure and form of a cable and/or a tether are readily apparent to one having ordinary skill in the art and therefore depiction in the figures is unnecessary. Similarly, depiction of a subsequent harness and/or belt is also unnecessary. It should be further appreciated that various types of securing lines are more suitable for the present force damper, e.g., stretchable and/or shock absorbing ropes, as additional force may be damped by these types of securing lines. However, including such types of securing lines is not required. 
     In some embodiments, stop  130  extends perpendicularly from shaft  128  towards first and second resilient members  106  and  108 , respectively. As such, it should be appreciated that stop  130  is positioned between first and second resilient members  106  and  108 , respectively, and second surface  116 . 
     In some embodiments, first and second resilient members  106  and  108 , respectively, are formed from a resilient polymer, a leaf spring, a shock absorber, and/or a compression spring, e.g., compression spring  146 . In some of these embodiments, resilient members  106  and  108  are compression spring  146 , and in some of these embodiments, compression spring  146  is formed from a chrome silicon steel material. 
     Although the foregoing clearly sets forth the structure and function of various embodiments of the present force damper, a further description of the components of one of the embodiments may be helpful to further understand how the device functions. In various embodiments, force damper  100  may include a variety of additional components and such components are not required in all embodiments. However, it should be appreciated that it is possible to include all or some of the components described below in a single embodiment if desired. 
     In view of the foregoing, force damper  100  may include plate  148 , reinforcement plate  136 , plate  142 , tubes  138 , stop  130 , tube  150 , shaft  128 , resilient members  106  and  108 , and connection points  118  and  132 . When all of the foregoing components are included in force damper  100 , the following non-limiting arrangement is just one of the possibilities. Tubes  138  partially enclose resilient members  106  and  108 . Tubes  138  are passed through openings  152  and  154  in plate  148  and subsequently through openings  156  and  158  in reinforcement plate  136  until ends  160  of tubes  138  abut plate  142 . Connection point  118  is fixedly secured to plate  148 . Stop  130 , which is secured to end  124  of shaft  128 , is positioned within openings  140  of tubes  138  and between resilient members  106  and  108  and plate  148 . The foregoing arrangement permits the linear movement of stop  130  against resilient members  106  and  108  when force damper  100  is arresting a first force imparted by an object moving in a first direction. Reinforcement plate  136  may further include opening  162  wherein tube  150  is passed until it abuts plate  142 . Tube  150  provides an unrestricted passage for shaft  128  during its linear displacement. Moreover, the combination of reinforcement plate  136 , tube  150  and plate  142  strengthens the overall structure of force damper  100 . Plate  142  may include through bore  120  adjacent to the abutment of tube  150 . Through bore  120  provides access to second end  126  of shaft  128  and thereby a means to secure connection point  132  to shaft  128 . As can be appreciated in view of the foregoing, the pathway of force through the device is: connection point  118  to plate  148  to tubes  138  to plate  142  to resilient members  106  and  108  to stop  130  to shaft  128  to connection point  132 . It is this arrangement that permits the damping of force between connection points  118  and  132 , in this particular embodiment. 
     The foregoing arrangement results in a force damper that solves problems presented by regulatory agencies and worker safety concerns, i.e., a force damper in a fall mitigation system should only be used one time. The foregoing embodiments provide force damping over a reduced range of travel, e.g., the present force damper travels approximately three to six inches while absorbing the force of a falling object. Heretofore, existing force damping systems required far greater distance to damp the force of a falling object, e.g., two and a half to three feet. It should be appreciated that the present force damper system may be configured to travel lesser or greater lengths depending on the needs of the system. All the various resilient members described above may provide some elastic deformation, the resilient members are selected for particular falling masses that will always impart plastic deformation on at least one of the resilient members while they arrest a first force imparted by an object moving in a first direction. For example, one set of resilient members may be rated for arresting the force created by a falling object ranging from 100 kilograms (kg) to 150 kg, while a different set of resilient members may be rated for falling objects ranging from 150 kg to 200 kg. It is critical that at least one of the resilient members experiences plastic deformation so that single use of each the devices can be ensured. The plastic deformation of at least one of the resilient members with no return to its original shape/size provides a readily observable characteristic of the present force damper that ensures a user of the device can determine if it has been previously used for its intended purpose, i.e., arresting the force created by an object moving in a first direction. 
     Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.