The disclosed concept relates generally to fall protection systems, and in particular, to horizontal lifeline systems. The disclosed concept also pertains to energy absorbers for use in horizontal lifeline systems.
In fall protection systems, a worker typically wears a safety harness. In some fall protection systems, the safety harness is attached to a horizontal lifeline system via a lanyard or another attachment mechanism. Horizontal lifeline systems typically span horizontally between attachment points such as anchors in a structure. In an arrest situation, such as when a worker falls, the horizontal lifeline system will deploy to slow and stop the fall of the worker. Horizontal lifeline systems often include an energy absorber that deploys in an arrest situation to reduce the forces applied to the worker in the case of a fall.
Energy absorbers typically consist of packaged tear webbing. In the event of a fall, the forces on the energy absorber cause the webbing to tear apart. The tearing absorbs energy, which slows the fall of the worker and reduces the impact forces on the worker. The webbing is generally packaged in a bag made of fabric. A fabric bag is a simple solution to packaging the energy absorber. However, the fabric bag is susceptible to wear and tear and can expose the webbing to wear and tear as well. There is room for improvement in energy absorbers.
When a horizontal lifeline system is installed, an amount of pre-tension should be applied to hold the horizontal lifeline taut and prevent it from sagging. If the amount of tension applied is too low, the horizontal lifeline system will sag. It is important that a sufficient amount of tension be applied to a horizontal lifeline. However, it is also desirable to have a simple and cost effective manner of determining whether sufficient tension has been applied. There is room for improvement in determining the tension of horizontal lifelines.
These needs and others are met by embodiments of the disclosed concept in which a cover for an energy absorber includes four cover pieces that interlock together to form the cover.
In accordance with one aspect of the disclosed concept, a cover for an energy absorber for use in a horizontal lifeline system comprises: four cover pieces structured to interlock together to form the cover, each cover piece including: an interlocking section structured to slide into the interlocking section of another one of the cover pieces; a number of tabs; and a number of tab receivers, wherein the number of tabs are structured to snap together with the tab receivers of another one of the cover pieces and the number of tab receivers are structured to snap together with the tabs of another one of the cover pieces.
In accordance with another aspect of the disclosed concept, a horizontal lifeline system comprises: a first termination arrangement structured to attach to a first anchor point; a second termination arrangement structured to attach to a second anchor point; a horizontal lifeline cable coupled to the first termination arrangement; an energy absorber coupled between the first and second termination arrangements, the energy absorber including webbing and a cover enclosing the webbing, the cover comprising: four cover pieces structured to interlock together to form the cover, each cover piece including: an interlocking section structured to slide into the interlocking section of another one of the cover pieces; a number of tabs; and a number of tab receivers, wherein the number of tabs are structured to snap together with the tab receivers of another one of the cover pieces and the number of tab receivers are structured to snap together with the tabs of another one of the cover pieces.
A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.
The horizontal lifeline system 10 includes termination arrangements 11,12 provided at each of its ends. The termination arrangements 11,12 are structured to attach to corresponding anchor points 4,5. The termination arrangements 11,12 may include, for example and without limitation, hooks, carabiners, rings, etc. While some examples of termination arrangements 11,12 have been provided, it will be appreciated by those having ordinary skill in the art that any suitable termination arrangements that are capable of attaching the horizontal lifeline system 10 to corresponding anchor points 4,5 may be employed without departing from the scope of the disclosed concept.
The horizontal lifeline system 10 further includes a tensioner 30 and a horizontal lifeline cable 20. The tensioner 30 and the horizontal lifeline cable 20 are disposed between the termination arrangements 11,12. One end of the tensioner 30 is attached to the horizontal lifeline cable 20. The tensioner 30 is coupled, either directly, or indirectly via one or more additional components, to one of the termination arrangements 12. The horizontal lifeline cable 20 is coupled, either directly, or indirectly via one or more additional components, to the other of the termination arrangements 11.
The tensioner 30 is structured to provide tension for the horizontal lifeline cable 20. In some example embodiments of the disclosed concept, the tensioner 30 may be a turnbuckle, such as twist turnbuckle, that may be twisted to increase or decrease the tension on the horizontal lifeline cable 20. However, it will be appreciated by those having ordinary skill in the art, that any suitable device for adjusting the tension of the horizontal lifeline cable 20 may be employed without departing from the scope of the disclosed concept.
The horizontal lifeline system 10 further includes an energy absorber 100 and a load indicator 200. The energy absorber 100 includes a cover 102 (shown in
The horizontal lifeline system 10 additionally includes a load indicator 200. The load indicator 200 is structured to provide an indication when the tension in the horizontal lifeline cable 20 reaches a predetermined level. In some example embodiments of the disclosed concept, the load indicator 200 includes a washer that is only able to spin freely once the tension in the horizontal lifeline cable 20 has reached the predetermined level.
Intermediate assembly steps are shown in
The cover piece 102a includes an interlocking section 110, tabs 120, and tab receivers 130. The interlocking section 110 is structured to slide into the interlocking section of another cover piece. The tabs 120 are structured to snap together with the tab receivers of another cover piece and the tab receivers 130 are structured to snap together with the tabs of another cover piece. Sliding and snapping together the four cover pieces 102a, 102b, 102c, and 102d in this manner results in the assembled cover 102.
The interlocking section 110 includes a first portion 112 and a second portion 114 (shown in
The cover piece 102a has a first side and a second side opposite the first side. The tabs 120 are disposed on the first side and the tab receivers 130 are disposed on the second side. When the cover piece 102a is snapped together with another cover piece 102d, the cover pieces 102a and 102d are inverted with respect to each other so that the tabs 120 of the cover piece 102a align with the tab receivers 130 of the other cover piece 102d (see
The tabs 120 include a snap member 122 and a depression 124. The tab receivers 130 include an opening 132 and a receiving track 134. The snap member 122 is structured to snap into the opening 132 of the tab receiver 130 of another cover piece 102d (see
In some example embodiments of the disclosed concept, the tabs 120 extend the height of the first side of the cover piece 102a and then continue beyond the end of the first side of the cover piece 102a. For example, the depression 124 may extend the entire height of the first side of the cover piece 102a. In some example embodiments, the snap member 122 may be disposed at an end of the depression 124 in an area extended beyond the height of the first side of the cover piece 102a. In this manner, the snap member 122 may extend into the interior of another cover piece 102c and snap into the opening 132 of the tab receiver 130 of the other cover piece 102c. Additionally, the tab 120 may extend into the receiving track 134 of the tab receiver 130 of the other cover piece 102c.
In some example embodiments, the snap member 122 has a triangular cross-section with a flat portion of the triangular cross-section being structured to corresponding to a side of the opening 132 of the other cover piece 102c. The cross-sectional shape of the snap member 122 allows the snap member 122 to easily slide into the tab receiver 130 and snap into the opening 132. However, the snap member 122 will not slide out of tab receiver 130 until the snap member 122 is snapped free from the opening 132.
In some example embodiments of the disclosed concept, the cover piece 102 has 3 tabs 120 and 3 tab receivers 130. The tabs 120 and tab receivers 130 are spaced along the length of the cover piece 102a. Each tab 120 has a corresponding tab receiver 130 disposed directly opposite of it so that when the cover piece 102a is snapped together with another cover piece 102c, the tabs 120 of the cover piece 102 align with the tab receivers 130 of the other cover piece 102c and vice versa. It will be appreciated by those having ordinary skill in the art that other numbers of tabs 120 and tab receivers 130 may be employed without departing from the scope of the disclosed concept.
The cover piece 102a may have a tapered shape. That is, one end of the cover piece 102a has a first height and the opposite end of the cover piece 102a has a second height that is less that the first height. The cover piece 102a includes a taper section 140. The taper section 140 tapers from the first height to the second height along across a portion of the length of the cover piece 102a. The taper section 140 may be disposed at an end of the cover piece 102a opposite the interlocking section 110. The resulting cover 102 may have a central portion, including the interlocking sections 110 that has a greater height than its end portions, as shown for example in
In an example embodiment of the disclosed concept, the four cover pieces include a first cover piece 102a, a second cover piece 102b, a third cover piece 102c, and a fourth cover piece 102d, as shown in
The circular openings 150 are formed from semi-circular openings 152 formed in the end of the cover piece 102a (shown in
In some example embodiments of the disclosed concept, the cover pieces 102a, 102b, 102c, and 102d are made of rigid material such as plastic. It will be appreciated that the cover pieces 102a, 102b, 102c, and 102d may be composed of other materials without departing from the scope of the disclosed concept.
The load indicator 200 further includes a fastener 206. The fastener 206 is structured to attach the first connector 202 to the second connector 204. In some example embodiments of the disclosed concept the fastener 206 includes a nut 214 and a bolt 216. The bolt 216 is threaded through openings in the first and second connectors 202,204 and then the nut 214 is attached to the bolt such that the first and second connectors 202,204 are disposed between the head of the bolt 216 and the nut 214. It will be appreciated by those having ordinary skill in the art that other types of fasteners may be employed without departing from the scope of the disclosed concept.
The load indicator 200 also includes a moveable member 210 disposed between the first and second connectors 202,204. The moveable member 210 is also disposed around the fastener 206. In some example embodiments of the disclosed concept, the moveable member 210 is a washer. However, it will be appreciated that other variations of the moveable member 210 may be employed without departing from the scope of the disclosed concept.
A first spring 208 is disposed between the head of the bolt 216 and the first connector 202. The first spring 208 is structured to apply bias to the fastener 206 to pull the first and second connectors 202,204 together. For example, the first spring 208 is disposed between the head of the bolt 216 and the first connector 202 and applies bias forces to the fastener 206 and the first connector 202 in opposite directions. These bias forces pull the nut 214, and thus the second connector 204 towards the first connector 202.
A second spring 212 is disposed between the second connector 204 and the moveable member 210. It will be appreciated that the second spring 212 may also be disposed between the first connector 202 and the moveable member 210. The second spring is structured to apply bias against the moveable member 210 to press the moveable member 210 against the first connector 202.
The load indicator 200 is structured to provide an indication when the tension across it is at or above a predetermined tension level. In some example embodiments of the disclosed concept, the predetermined tension level is about 400 lbs. However, it will be appreciated by those having ordinary skill in the art that any predetermined tension level may be employed without departing from the scope of the disclosed concept. The indication provided by the load indicator 200 is the ability of the moveable member 210 to spin freely about the fastener 206. That is, when the tension across the load indicator 200 is less than the predetermined tension level, the moveable member 210 is not able to spin freely about the fastener 206. When the tension across the load indicator 200 is at or greater than the predetermined tension level, the moveable member 210 is able to spin freely about the fastener 206. In this manner, a worker may attempt to spin the moveable member 210 to check whether sufficient tension has been applied to the horizontal lifeline cable 20.
For example, when the load indicator 200 is manufactured, the bolt 216 and nut 214 are tightened relative to each other such that the second spring 212 is compressed but the first spring 208 is only partially compressed (e.g., in the state shown in
In some example embodiments of the disclosed concept, the first and second springs 208,210 are able to compress different distances. For example, the first spring 208 may compress a further distance than the second spring 210. That is, the difference between the compressed and expanded length of the first spring 208 is greater than the difference between the compressed and expanded length of the second spring 210. The first and second springs 208,210 may be selected such that the first spring 208 compresses by enough distance at the predetermined tension level such that the distance between the first and second connectors 202,204 increases enough that the second spring 212 expands and no longer biases the moveable member 210 against the first connector 202.
In some example embodiments, the first spring 208 and the second spring 212 may be comprised of one or more disc springs such as belleville washers. However, it will be appreciated that other types of springs may be employed without departing from the scope of the disclosed concept. In an example embodiment, the first spring 208 is comprised of a plurality (e.g., without limitation, 4) disc springs and the second spring 212 is comprised of one disc spring. However, it will be appreciated that different number of disc springs may be employed in the first and second springs 208,212 without departing from the scope of the disclosed concept. In some example embodiments of the disclosed concept, the first spring 208 has a higher biasing force than the second spring 212. It will also be appreciated by those having ordinary skill in the art that the second spring 212 may be omitted. For example, the bias force applied by the first spring 208 may be sufficient to prevent the moveable member 210 from spinning freely when the tension across the load indicator 200 is less than the predetermined tension level.
The energy absorber 100 and the load indicator 200 may be employed together in a horizontal lifeline system 10 such as that shown in
While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.
This application is related to co-pending U.S. patent application Ser. No. __/___,___ filed on ______, entitled “LOAD INDICATOR AND HORIZONTAL LIFELINE SYSTEM INCLUDING THE SAME” (Attorney Docket No. 302046-00051), the entirety of which is incorporated herein by reference.