WO2012145639A2 - Safety harness with resilient energy absorbing element - Google Patents

Abstract

A safety harness connectable between a user and a fixed object comprising an energy absorbing element, and straps that connect between the energy absorbing element, the user and a fixed base. The energy absorbing element comprises a molded polymeric block having tensile strength and elongation properties to absorb energy. It is a block of polymeric material designed to take advantage of a proprietary process that orients the crystalline structure of the device which increases tensile strength and add elasticity required to absorb fall energy. In one form a slack portion limits elongation of the energy absorbing element.

Description

SAFETY HARNESS WITH RESILIENT ENERGY ABSORBING ELEMENT

Cross -Reference to Related Application

[0001] This application claims the benefit pursuant to Title 35 USC § 119 to Provisional Application No. 61/477,974, filed April 21, 2011, the entire content of which is hereby incorporated by reference as if fully set forth herein.

Background of The Invention

[0002] This disclosure relates to personal safety harness and, in particular, to such harness with a molded energy absorbing element capable of resilient elongation.

[0003] Energy absorber devices are used throughout the vertical occupation industry to protect window washers, linemen, roofers, arborists, lumberjacks, and others in high-elevation occupations against the dangers associated with a fall. The absorbing device is attached to safety harness or lanyard between the user and a secure base structure. It is designed to absorb energy of the fall and also limit the total distance traveled in an accidental fall from a secure structure.

[0004] The safety lanyard deploys until the energy absorber in the system becomes operative and essentially absorbs energy of the fall. The user decelerates as energy is absorbed and will not receive the full impact force of the fall.

[0005] Typical industry absorbers are a complex construction of sewn-high strength webbing. The webbing is sewn in a method that allows the webbing to "tear" away from its original steady state position when a force (impact load) or fall energy is applied to the device. The system works, but the user does feel a relatively strong impact force as the webbing tears away as required. Also, the torn webbing is no longer useable for energy absorption.

Summary of the Disclosure

[0006] The design of the present disclosure includes an elastomeric energy absorbing element interposed in the safety line. It is a molded polymeric block made by a process that orients the crystalline structure of the device, to increase tensile strength and add elastic, stretch properties. If a user encounters a fall from an elevated working position, the device will stretch (elongate) and absorb the fall energy so the energy does not shock or excessively impact the user on full extension of the safety line when it becomes fully taut. The energy absorbing element has the capability to return to its original shape when the load is removed.

[0007] The block configuration can be "programmed or tuned" to meet specific load and deflection requirements for the industry via its molded geometry. The block is designed to take advantage of a proprietary process that orients the crystalline structure of the device which increases tensile strength and adds the elasticity required to absorb fall energy.

Description of the Drawings

[0008] Fig. 1 is a plan view of a personal safety harness of the present disclosure with an included energy absorbing element;

[0009] Fig. 2 is a partial plan view illustrating details of an energy absorbing element for the personal safety harness such as shown in Fig. 1;

[0010] Fig. 3 is a plan view of an energy absorbing element body blank after molding, and prior to deforming;

[0011] Fig. 4 is a side view of the energy absorbing element body blank of Fig. 3;

[0012] Fig. 5 is an end view of the energy absorbing element body blank of Fig. 3;

[0013] Fig. 6 is a cross-sectional view of the energy absorbing element body blank shown in Fig. 3, taken along line 6-6 of Fig. 3;

[0014] Fig. 7 is a cross-sectional view of the energy absorbing element body blank shown in Fig. 3, taken along line 7-7 of Fig. 3;

[0015] Fig. 8 is a cross-sectional view of the energy absorbing element body blank shown in Fig. 3 taken along line 8-8 of Fig. 3;

[0016] Fig. 9 is a cross-sectional view of the energy absorbing element body blank shown in Fig. 3, taken along line 9-9 of Fig. 3;

[0017] Fig. 10 is a plan view of the energy absorbing element of Fig. 2 showing the energy absorbing element after being subjected to a deforming step;

[0018] Fig. 11 is a side view of the energy absorbing element of Fig. 10;

[0019] Fig. 12 is an end view of the energy absorbing element shown in Fig. 10;

[0020] Fig. 13 is a cross-sectional view of the energy absorbing element shown in Fig. 10, taken along line 13-13 of Fig. 10; [0021] Fig. 14 is a cross-sectional view of the energy absorbing element shown in Fig. 10, taken along line 14-14 of Fig. 10;

[0022] Fig. 15 is a cross-sectional view of the energy absorbing element shown in Fig. 10, taken along line 15-15 of Fig. 10;

[0023] Fig. 16 is a cross-sectional view of the energy absorbing element shown in Fig. 10, taken along line 16-16 of Fig. 10;

[0024] Fig. 17 is a side view of the energy absorbing element such as shown in Fig. 2 with attached connection elements and a limit strap secured with encircling straps;

[0025] Fig. 18 is a side view of an alternative arrangement of a personal safety harness having an energy absorbing element;

[0026] Fig. 19 is a side view of a personal safety harness with an energy absorbing element and limit strap encased in a releasable cover;

[0027] Fig. 20 is a view of an alternative form of energy absorbing element for use in a personal safety harness;

[0028] Fig. 21 is a view of an alternative form of energy absorbing element for use in a personal safety harness.

Detailed Description

[0029] A personal safety harness 210 in accordance with the present disclosure is illustrated in Fig. 1. It includes elastic energy absorbing element 212 with eyelets 213 at each end provided with connection elements 214. One connection element 214 is connected to an attachment strap portion 215 to connect to a user. The connection element 214 at the other end of energy absorbing element 212 is connected to a flexible securement strap portion 216 to be attached to a fixed base (not shown). Should the user fall from an elevated structure, the straps become taut to the element 212 and all energy of the falling body is delivered to energy absorbing element 212.

[0030] As shown in Fig. 1 the energy absorbing element 212 may be combined with a slack or limit strap portion 217 that also extends between the connection elements 214. The limit strap is of a length that exceeds the length of the elongated energy absorbing element 212, usually about twice as long or longer. It includes end loops that connect to the connection elements 214. It limits the permissible extension of energy absorbing element 212 on application of tensile loading at its ends.

[0031] The personal safety harness 210 has attachment hooks 219 in the form of standard carabineers at opposite ends, for connection to the user, and to the secure base structure. A typical safety harness assembly 210 may have a length of about six to nine feet between hooks 219. It is expected that the energy absorbing element 212 may be about one to one and one -half feet in unstressed length between eyelets 213. These lengths are only illustrative and not limiting. Specific dimensions are developed for each application, considering weight of load, permissible free fall distance, permissible elongation and elastic limit of element 212 and other factors.

[0032] Elastic energy absorbing element or block 212 is molded from a polymeric material that provides the qualities of energy absorption on elongation and resiliency sufficient to restore the element to its original, or nearly original, length after initial elongation. These properties provide the desired safety feature of cushioning the impact of an accidental fall by a user of the safety harness and renders the device available for subsequent protection.

[0033] The block is designed via a proprietary ITW (Dahti) process that orients the crystalline structure of the device which increases tensile strength and adds the elasticity required to absorb fall energy. It is made available by ITW-Nexus, Des Plaines, IL.

[0034] The block can be "programmed or tuned" to meet specific load and deflection requirements for the industry via the molded geometry. Customer specific "end treatment" shapes and line loop designs can be molded directly into the block. The elastic element of the present disclosure for fall energy absorption in prototype mock-ups appears to improve the impact-load-force absorption/dampening versus the current industry standard. It also appears to have a "softer" feel as the device is activated by a fall.

[0035] The ability to tune or program the design allows for this device to be used in other disciplines as well. Specific harness and gear load dampening can be built directly into a safety harness by adding an elastic energy absorbing element to the system. For example, alternative configurations of suitable energy absorbing elements are shown in Figs. 20 and 21. Each such element, designated 512 in Fig. 20 and 612 in Fig. 21 is made from the polymeric material described herein and configured to provide elongation properties suitable for a given application. Each is processed as described herein to achieve the intended functionality. [0036] The configuration of the energy absorbing element may vary, depending on the desired properties to be imparted to it. An example of an energy absorbing element suitable for the embodiment of a safety harness as described in connection with Fig. 1 is illustrated in Figs. 2 and 10 to 16:

[0037] In an aspect of the illustrated form of suitable energy absorbing element comprising a a thermoplastic body 112 is a monolithic, elastomeric, thermoplastic component, having at least one non-deformed region in the body having dimensions established by molding of the body; and at least one deformed region in the body, deformed after molding to have a deformed dimension greater than the dimension thereof created by molding, with the deformed dimension resulting from elongation beyond the elongation anticipated for use of the thermoplastic body.

[0038] Figs. 10 to 16 illustrate the geometry of the exemplary thermoplastic body of energy absorbing element 112 illustrating the shapes and relative areas along various cross sections. These illustrations show the geometry of a final processed thermoplastic body of the energy absorbing element 112 after it has been deformed in accordance with one suitable deforming process as described in more detail in reference to Figs 3 to 9.

[0039] Referring now more specifically to Figs. 2 and 10 through 16, an exemplary personal safety harness 110 having an energy absorbing element comprises a molded thermoplastic body 112 and a pair of connection elements in the form of rings 114 mounted to opposite ends. The size, shape and configuration of body 112 may vary from application to application depending, in large part, on the desired characteristics of the finished energy absorbing element 112.

[0040] In the illustrated exemplary embodiment, thermoplastic body 112 generally includes a pair of end portions 118 that are joined by a central intermediate region 120 having a plurality of alternating nodes 122 and connectors 124. Some, but not all of the nodes 122 and connectors 124 are identified with reference numerals in the drawings. In the illustrated exemplary embodiment, end portions 118 are regions of an essentially uniform thickness selected so that the end portions 118 do not undergo significant deformation during the deforming process to be described subsequently. It may, however, be acceptable for end portions 118 to undergo significant deformation in some applications and uses of pre-deformed thermoplastic bodies.

[0041] Each end portion 118 of the illustrated embodiment defines two longitudinally spaced apertures 126 for receiving attachment elements, illustrated as rings 114. Apertures 126 may be surrounded by an integral molded boss 127 to, among other things, reduce the likelihood of damage at the interface with rings 114. The number and spacing of apertures 126 may vary from application to application, as desired. The size, shape and configuration of the end portions 118 and any mounting features incorporated into the end portions 118 may vary from application to application. The mounting features may be essentially any structure suitable for mounting the mounting to the molded body and associated flexible strips of the safety harness.

[0042] As noted above, central region 120 of thermoplastic body 112 includes alternating nodes 122 and connectors 124. Nodes 122 are regions of generally greater cross sectional areas than the cross sectional areas of connectors 124. As a result, nodes 122 present greater resistance to deformation during manufacture, and greater resistance to elongation when placed under a load during use. The cross sectional areas of nodes 122 and connectors 124 may vary from application to application, depending in part on the desired characteristics of the finished elastic energy absorbing element 112.

[0043] In the embodiment illustrated in Figs. 2, and 10 to 16, nodes 122 and connectors 124 are configured to define two substantially parallel strands 130 and 132; each strand 130, or 132 including a series of alternating nodes 122 and connectors 124, and each strand 130 and 132 extending from one end portion 118 to the other end portion 118. The nodes 122 on parallel strands 130 and 132 may be joined in select locations. In the illustrated exemplary embodiment, the first three sets of nodes 122 at each end of the central region 120 are joined together by integrally formed bridges 134 that extend between strands 130 and 132. Bridges may cooperate with nodes 122 and connectors 124 to define spaces 136.

[0044] The number and characteristics of the bridges 134 may be selected as one factor in providing the finished elastic energy absorbing element 112 with desired characteristics. For example, additional bridges 134 may be included to stiffen the element 112 against lateral deflection.

[0045] In the illustrated embodiment, adjacent nodes 122 are joined by a single connector 124. The number of connectors 124 joining the nodes 122 may vary from application to application, and from location to location within a single element. In the illustrated embodiment, nodes 122 and connectors 124 are generally aligned in a longitudinal direction, but they need not be aligned in all embodiments.

[0046] In the illustrated embodiment, thermoplastic body 112 includes a plurality of substantially equal-sized, regularly spaced nodes 122 and substantially equal-sized, regularly spaced connectors 124. Nodes 122 and connectors 124, however, need not be of equal size nor have regular spacing along the strands 130 and 132. To the contrary, nodes 122 and connectors 124 may vary in size, shape, spacing or other characteristics from application to application to allow the "in use" characteristics of the elastic energy absorbing element 112 to be tuned. In some applications, the characteristics of nodes 122 and connectors 124 may vary in different regions of thermoplastic body 112 to provide localized control over the characteristics of thermoplastic body 112 in the different regions. For example, select regions may be stiffened by adjusting the characteristics of nodes 122 and/or connectors 124 in that region. Although the nodes 122 and connectors 124 of this embodiment have a substantially oblong-circular cross section, they may vary in cross-section from application to application. For example, nodes 122 and connectors 124 with circular, square, triangular, rectangular or irregular shaped cross- sections may be desired in certain applications. It should also be noted that the nodes 122 and connectors 124 of the illustrated embodiment share substantially similar cross sectional shapes that vary primarily only in scale. Nodes 122 and connectors 124 need not be similar in cross sectional shape, but may vary as desired. Although the illustrated embodiment includes the same number of nodes 122 and connectors 124 in each strand 130 or 132, the numbers may vary from application to application, if desired.

[0047] Referring to Figs. 3 to 9, a thermoplastic body blank 12 is manufactured in a process involving molding as a monolithic body with integral end portions 18, integral nodes 22 and connectors 24. The process includes mounting the molded part on a fixture that mates to the end portions 18 and elongating the element by stretching with a load well beyond any load the element is anticipated to experience in use, thereby effectively stretching the element well beyond its yield point and consequently creating a new higher yield point. After deformation, as long as the deformed element does not experience a load approaching the new higher yield point, it will not creep. It is contemplated that the thermoplastic body blank 12 may be elongated to at least one half to five times its original length. Preferably the thermoplastic body blank 12 may be elongated to at least twice its original length.

[0048] In the illustrated embodiment, the molded thermoplastic body blank 12 is formed using conventional injection molding techniques and apparatus. For example, the thermoplastic body blank 12 may be injection molded using a conventional injection molding apparatus (not shown) having a die that is configured to provide a part with the desired shape and features. In this embodiment, the thermoplastic body blank 12 is manufactured by injecting the desired material into a die cavity. The die is designed to provide a molded part (Figs. 3 to 9) that will take on the desired final shape of an energy absorbing element with thermoplastic body 112 (Figs. 10 to 16) once any desired deformation has taken place. In other words, the die is configured to form a part that will have the desired shape and dimensions after the deformation step is complete. Although injection molding is expressly described, the thermoplastic body blank 12 may be formed using other molding techniques and apparatus.

[0049] The pre-deformed thermoplastic body or elastic energy absorbing element seen in Figs. 3 to 9 can include integral end detail for attachment and deformed regions designed to perform elongation and recovery all in one injection molded member. Body rate and creep resistance are programmed into the body after molding by selective deformation to a

predetermined length that will generate the appropriate creep resistance and body tension. Nodes or unique regions within the element can provide special performance such as attachment, integral stop members, integral cams, etc.

[0050] The tension of the part is programmed during the formation process by controlling the ratio of molded size to deformed size. For example, a part blank that is molded at 10 inches long and then deformed to 10.1 inches in length will have a different body rate than a part blank that is molded at 10 inches long and deformed to 15 inches. In this example, the body rate difference will be more than 50%. The body is deformed by stressing beyond the load it will experience in use, to ensure that the body does not elongated any further in use, since it has been pre-deformed beyond that level before use.

[0051] The molded thermoplastic body blank 12 may be manufactured from a variety of elastomeric materials depending on the requirements of the specific application. More specifically, the thermoplastic body blank 12 may be manufactured from a TPE (Thermoplastic Elastomer) material, such as a COPE (Copolyester) material or a TPU (Thermoplastic Urethane) material. In the illustrated embodiment, the thermoplastic body blank 12 is molded from a thermoplastic polyether ester elastomer block copolymer. Suitable materials of this type include those available from DuPont under the Hytrel® trademark, and available from DSM under the Arnitel® trademark. In the illustrated embodiment, the material may have a Durometer in the range of 25-65 on the Shore D scale. In the illustrated embodiment, the molded body is molded from DSM EM400 or similar materials in the TPE family, especially COPEs and urethanes. [0052] After molding, the thermoplastic body blank 12 of Figs. 3 to 9 may be stretched or otherwise deformed. In one embodiment, the molded thermoplastic body blank 12 is deformed in the longitudinal direction to provide creep resistance and elasticity in the direction of deformation. The thermoplastic body 12 is deformed by increasing the alignment of the crystalline structure of the elastomeric material on a molecular level so that the support and other load bearing characteristics are altered. More particularly, a molded, un-deformed elastomeric thermoplastic body blank 12 typically includes a plurality of spherulites, which are created during the growth of the polymer by the formation of crystalline lamellae in helical strands radiating from a nucleation point. In its final form seen in Figs. 10 to 16, after deformation, thermoplastic body 112, at least some of the spherulites are destroyed and the crystalline lamellae are aligned in one direction. Typically, the final thermoplastic body 112 will be deformed to such a degree that the deformed thermoplastic body 112 has materially different load bearing characteristics in the deformed direction.

[0053] One method for deforming the thermoplastic body blank 12 is through stretching. If deformation is achieved through stretching, the precise amount of stretch to be applied to a given part will depend on the configuration of the part and the desired support characteristics. In many applications, it will be desirable to stretch the thermoplastic body blank 12 to at least twice, and possibly three times, its original length to achieve the desired alignment. The thermoplastic body blank 12 may be stretched using conventional techniques and apparatus. In one embodiment, a set of clamps may be configured to clamp onto the end portions 18 of the thermoplastic body blank 12 during stretching. As another example, the end portions 18 may be secured to a fixture by attachment elements or bolts passing through apertures 26 in the end portions 18. Because the thermoplastic body 12 is stretched beyond its elastic limit, it recovers to an intermediate dimension that is greater than its original length as molded, with the precise amount of elongation being dependent in large part on the geometry and material characteristics of the thermoplastic body material. This deformation is a non-recoverable, permanent deformation. As a result of this non-recoverable deformation, a degree of permanent deformation is removed from the deformed thermoplastic body such that when subsequent stresses on the deformed

thermoplastic body within the desired normal operating load are applied (for example in the range of approximately 150 to 300 lbs. load or more), the thermoplastic body resists permanent deformation over time (i.e. creep). [0054] In one embodiment, a cyclic deformation may be performed, wherein the membrane is deformed by stretching to a first distance, then relaxed to a second, intermediate distance, and then stretched to a second distance that could be lesser than, equal to or greater than the first distance. The sequence may be repeated as many times as necessary to achieve the desired deformation. The amount of time between cycles may vary. For example, in one embodiment, the membrane is stretched to 2 times its original length, relaxed to the original length (or until slack is present), then stretched to 1 ¾ times the original length.

[0055] The molded thermoplastic body blank 12 may be deformed with acceptable deforming processes that result in a deformed thermoplastic body 112 with different geometry and moment of inertia properties. Deformed thermoplastic body 112 includes nodes 122 and connectors 124 in strands 130 and 132. As can be seen in the figures, end portions 118 of the deformed thermoplastic body 112 remain substantially unchanged after deforming. The connectors 124 have, however, undergone a material change in length and cross-sectional area. The length 52 (Fig. 3) of connectors 24 is approximately 0.252" prior to deforming and approximately 0.395" following deforming (connector length 152 shown in Fig. 10). During deforming, the connector length reaches a maximum of 0.97" at maximum deforming distance.

[0056] In the exemplary embodiment, after deforming, a post deforming node width 140 (Figs. 13 and 14) remains at .63 inch (ref. 40 in Fig. 6 and 7), and a post deforming node to node height 142 shown in Figs. 14 and 15 (ref. 42 in Figs. 6 and 7) remains at 1.07 inch. The post deforming connector width 144 (Fig. 15) is .43 inch (ref. 44 in Fig. 8) and the connector to connector height 146 in Fig. 15 is .91 inch (ref. 46 in Fig. 8). End portion 118 has an end portion width 148 (Fig. 16) of .50 inch (ref. 48 in Fig. 9) and an end portion height 150 of 1.07 inch (ref. 50 in Fig. 9).

[0057] Although the elastomeric thermoplastic body blank 12 may be deformed by stretching, it may be possible in some applications to deform the thermoplastic body blank 12 using other processes. As an alternative to stretching, the thermoplastic body blank 12 may be deformed by compression. For example, it may be possible to deform certain materials by hammering, pressing or other forms of compression. In one embodiment for deforming by compression, the thermoplastic body blank 12 may be placed in a die or other structure (not shown) that constrains the thermoplastic body blank 12 on all sides other than at least one side that corresponds with the desired direction of deformation. Opposed sides may be unconstrained to permit the material of the thermoplastic body blank 12 to flow from both sides along the direction of deformation. Alternatively, only a single side may be unconstrained, thereby limiting material flow to a single side. A compressive force is then applied to the part. For example, a press can be used to compress the thermoplastic body blank 12 within the die.

Sufficient compressive force is applied so that the material begins to flow in the unconstrained direction. This in effect causes the thermoplastic body blank 12 to extend, and its crystalline structure to become increasingly aligned in the direction of deformation. The amount of force applied to the thermoplastic body blank 12 may vary from application to application, depending on the desired degree of alignment or deformation.

[0058] Although deformation of the entire elastomeric thermoplastic body blank 12 is appropriate in some applications, it is not necessary to deform the entire thermoplastic body blank 12. Rather, in some applications, it may be desirable to deform only select portions or regions of the membrane as described. For example, in some applications it may be desirable to deform only select peripheral portions of the membrane. When desirable, this may be achieved by applying localized stretching or localized compression of the thermoplastic body blank 12.

[0059] Various parameters of the deforming process may be varied to provide a deformed thermoplastic body 112 with the desired characteristics. For example, the amount of elongation, the speed at which the elongation is applied (which may be constant or variable), the dwell time (i.e. the amount of time the thermoplastic body blank 12 is held in an elongated condition), the method used to attach the thermoplastic body blank 12 to the deforming fixture, and the number of cycles (e.g. the number of times the thermoplastic body blank 12 is elongated) can be varied to affect the characteristics of the finished energy absorbing element. A slow, controlled stretch aids in maintaining a uniform deformation across the connectors 24 of the thermoplastic body blank 12. A cyclic deformation process helps compensate for any irregularities within the thermoplastic body blank 12 material to provide a uniform stretch because areas of greater or lesser stretch may even out after multiple cycles. The time between molding and deforming may also be adjusted. For example, in one embodiment, the molded thermoplastic body blank 12 is stretched within a short time, such as 10-15 minutes, after it is removed from the mold, so that the thermoplastic body blank 12 is still warm when it is stretched. This reduces the force that is necessary to stretch and therefore deform the thermoplastic body blank 12. [0060] Referring to Fig. 2, once the thermoplastic body 112 is molded and deformed, pre- manufactured rings 114 are added to opposite ends of the energy absorbing element 112. The rings may be attached to any mounting aperture 126 as desired.

[0061] As seen in Fig. 17, as an option, the energy absorbing element, designated 412 may directly receive attachment hooks, such as attachment hooks 419 illustrated as carabineers for connection to other webbing forming an attachment strap and securement strap to provide a safety harness assembly such as illustrated in Fig. 1 or 2. In this arrangement, a limit strap 417 extends between the carabineers 419.

[0062] In the configuration illustrated in Fig. 17, limit strap 417 is folded upon itself and releasably attached to energy absorbing element 412 by hook and loop wraps 440. This configuration minimizes the profile of the device when not activated. On elongation of the energy absorbing element 412, the hook and loop wraps 440 release and the limit strap 417 is free to limit maximum extension of the element 412.

[0063] As seen in Figs. 18, the safety harness 310 may take the form of a continuous rope, lanyard or cord secured to apertures in energy absorbing element 312, similar to the energy absorbing element 112 described in connection with Figs. 2 and 10 to 16. It is equipped with attachment hooks 319 at each end. The rope is continuous and forms attachment portions 315, securement portion 316 as well as a limit strap portion 317. Knots 331 secure the rope to an energy absorbing element 312, for example, at apertures, such as apertures 126 seen in Fig. 2 and divide the rope into the separate portions 315, 316, and 317.

[0064] Limit strap portion 317 is of a predetermined length sufficient to permit the extension or elongation of energy absorbing element 312 on application of tensile loading between hooks 319. It is usually at least twice as long as the unstressed length of energy absorbing element 312.

[0065] As illustrated, the rope is passed through spaces or gaps in energy absorbing element 312 such as spaces 136 seen in Fig. 2. On tensile loading of energy absorbing element 312, the element 312 will extend or elongate and the rope will exit. On reaching the maximum length of rope, it will become taut between apertures.

[0066] As shown in Fig. 19, the combined energy absorbing element 312 and limit strap portion 317 may be covered with a removable or "break-away" cover 333. The cover may be releasably secured with attached hook and loop wraps 340. In the event of a fall by the user, the energy absorbing element 312 elongates which causes the cover 333 to open and fall away. [0067] Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain he best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.

Claims

CLAIMED IS:

A personal safety harness comprising:

an energy absorbing element;

a flexible strap connectable between a user and a base comprising:

an attachment portion connected to one end of said energy absorbing element and connectable to a user;

a securement portion connected to the other end of said energy absorbing element and connectable to a base;

said energy absorbing portion comprising a molded monolythic block that absorbs energy through elongation.

2. A personal safety harness as claimed in claim 1 wherein said energy absorbing element is a molded block of polymeric material having an oriented crystalline structure.

3. A personal safety harness comprising an energy absorbing element as claimed in claim 2 wherein said energy absorbing element includes at least one region deformed by elongation prior to connection to said flexible strap portions.

4. A personal safety harness comprising an energy absorbing element as claimed in claim 3 wherein said energy absorbing element has a body having end portions connected respectively to said attachment portion and said securement portion, joined by a central intermediate region including alternating nodes and connectors.

5. A personal safety harness comprising an energy absorbing element as claimed in claim 4 wherein said end portions are of essentially uniform thickness, resistant to significant deformation.

6. A personal safety harness comprising an energy absorbing element as claimed in claim 5 wherein said nodes comprise regions of greater cross-sectional area than said cross- sectional area of said connectors.

7. A personal safety harness comprising an energy absorbing element as claimed in claim 4 wherein said intermediate region comprises two substantially parallel strands, each strand including a series of alternating nodes and connectors extending from one end portion to said other end portion.

8. A personal safety harness comprising an energy absorbing element as claimed in claim 7 wherein said central intermediate portion includes integrally formed bridges connecting at least a portion of said nodes on one of said strands to nodes on the other of said strands.

9. A personal safety harness comprising an energy absorbing element as claimed in claim 3 wherein said energy absorbing element is elongated from about one-half to about five times its original molded length.

10. A personal safety harness comprising an energy absorbing element as claimed in claim 9 wherein said energy absorbing element is elongated to at least about twice its original length.

11. A personal safety harness comprising an energy absorbing element as claimed in claim 6 wherein said energy absorbing element is elongated from about one-half to about five times its original molded length.

12. A personal safety harness comprising an energy absorbing element as claimed in claim 11 wherein said energy absorbing element is elongated to at least about twice its original length.

13. A personal safety harness comprising an energy absorbing element as claimed in claim 7 wherein said energy absorbing element is elongated from about one-half to about five times its original molded length.

14. A personal safety harness comprising an energy absorbing element as claimed in claim 13 wherein said energy absorbing element is elongated to at least about twice its original length.

15. A personal safety harness as claimed in claim 1 wherein said flexible strap includes a slack portion connected between said ends of said energy absorbing element having a length that exceeds the length of said energy absorbing portion.

16. A personal safety harness as claimed in claim 15 wherein said slack portion has a length at least twice the length of said energy absorbing portion.

17. A personal safety harness as claimed in claim 15 wherein said attachment portion, said securement portion, and said slack portion comprise a continuous element.

18. A personal safety harness as claimed in claim 15 wherein aid energy absorbing element includes a plurality of apertures and a portion of said slack portion is disposed in said apertures.

19. A personal safety harness as claimed in claim 15 wherein said harness includes a cover surrounding said energy absorbing element and said slack portion.

20. A personal safety harness as claimed in claim 15 wherein said harness includes at least one releasable web surrounding said slack portion and said energy absorbing element.