Device for absorbing and dissipating the energy of a dropped or thrown object

Abstract

A device for absorbing and dissipating the energy of a dropped or thrown object is disclosed. The device includes a flexible planar layer (mesh layer), energy absorbing and dissipating elements (ligatures), a frame, and a void-space between the mesh layer and the supporting surface where the frame rests, for example, a floor, foundation, or wall. The mesh layer is connected to the frame by energy absorbing and dissipating ligatures. The falling or thrown weight contacts and deflects the mesh layer, causing the ligatures to elongate in tension and absorb and dissipate a portion of the kinetic energy of the weight. Also, the friction between the deforming elements of the mesh layer contributes to the kinetic energy dissipation. The remaining kinetic energy is transferred to the frame and the supporting surface. The void-space allows the falling weight in contact with the mesh layer to decelerate over a greater distance and time, thereby reducing the total dynamic force applied to the frame and the surface on which the frame rests.

Claims

1. A device for dissipating an initial impact energy and reducing an initial impact force of a moving object, the device comprising: a rigid frame, supported by a horizontal or vertical supporting structure, wherein the frame surrounds and defines a frame interior void, and wherein the frame has a frame base, multiple frame sides, and an open frame top, and wherein the frame has a frame length, a frame width and a frame depth, and wherein the frame top and/or the frame sides contain multiple perimeter connectors; at least one flexible, planar, mesh layer, wherein the mesh layer comprises interlaced webbing, and wherein the mesh layer has a mesh perimeter, and wherein the mesh perimeter is connected to the perimeter connectors by one or more viscoelastic ligatures; wherein, upon the moving object imparting the initial impact force to the mesh layer, the mesh layer undergoes a mesh layer deflection into the interior void through an impact distance and an impact time, such that the mesh layer deflection is operative to extend the impact distance and the impact time, thereby reducing the initial impact force to a lesser resultant impact force imparted to the supporting structure; wherein, upon the moving object imparting the initial impact force to the mesh layer, the viscoelastic ligatures cooperatively and concurrently undergo a viscoelastic elongation, whereby the ligatures are operative to transfer a first impact kinetic energy component of the initial impact energy to the frame, and to dissipate viscously a second impact kinetic energy component of the initial impact energy, and to store a first elastic strain potential energy component; wherein, in the course of the mesh layer deflection, the mesh layer is stretched, such that an internal mesh deformation friction dissipates a third kinetic energy component of the initial impact energy, while a mesh elasticity stores a second elastic strain potential energy component; and wherein, during a rebound of the moving object after reaching the impact distance, the conversion of the first elastic strain potential energy component to a first rebound kinetic energy component is damped by a viscous relaxation of the viscoelastic ligatures, and the conversion of the second elastic strain potential energy component to a second rebound kinetic energy component is damped by an internal mesh recovery friction of the mesh layer, such that a height and a number of rebounds of the moving object is diminished.

2. The device according to claim 1, wherein the frame is comprised of one or more interconnected frame sections having sectional shapes comprising arcs, chords, semi-circles, semi-ovals, semi-ellipses, figures-8, circles, ovals, ellipses and/or polygons, and wherein the frame has a frame cross-section that is rectangular, trapezoidal or semi-trapezoidal in shape.

3. The device according to claim 2, wherein a frictional interaction between the interlaced webbing of the mesh layer increases the internal mesh deformation friction and the internal mesh recovery friction of the mesh layer.

4. The device according to claim 3, wherein the viscoelastic ligatures comprise one or more continuous or semi-continuous, looped, unbraided or braided strands of a rubber or plastic elastomer.

5. The device according to claim 4, wherein the perimeter connectors comprise bolts, screws, rivets, hooks, rings, eyelets, grommets, clamps, snaps, and/or hook-and-loop straps, or wherein the perimeter connectors comprise apertures, notches, grooves, channels, flanges and/or protrusions of the frame.

6. The device according to claim 5, wherein the perimeter connectors are extendable and/or rotatable, so as to adjust a tension of the ligatures in relation to the initial impact force of the moving object.

7. The device according to claim 2, wherein the frame length, the frame width, the frame depth, the frame shape and the frame cross-section are correlated to the initial impact force of the moving object.

8. The device according to claim 4, wherein the viscoelastic ligatures are made of paraffin-infused butyl rubber.

9. The device according to claim 3, wherein the webbing is made of paraffin-infused butyl rubber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic of a force-elongation curve for a fully elastic ligature.

(2) FIG. 2 is a schematic of a force-elongation curve for an energy dissipating viscoelastic ligature.

(3) FIG. 3 is acceleration data for a fully elastic and a viscoelastic ligature during dynamic impact tensile elongation.

(4) FIG. 4 is a perspective view of an embodiment of the device for reduced impact force and reduced sound and vibration transmission.

(5) FIG. 5 is a cross-sectional view of the device in FIG. 4, along the line A-A, showing the void space and the frame with a rectangular cross-section.

(6) FIG. 6 is a top plan view of the device in FIG. 4, showing the frame in a Figure-8 shape.

(7) FIG. 7 is a cross-sectional view of the device in FIG. 6, along the line B-B, showing an embodiment with two mesh layers, one above the other.

(8) FIGS. 8A-8G depict top plan views of frame shapes consisting of ellipse, circle, hexagon, elliptical figure-8, hexagonal figure-8, rectangle, and square, respectively.

(9) FIGS. 9A-9E depict cross-sectional views of the frame in FIG. 8F, along the line C-C consisting of rectangular, trapezoidal, semi-trapezoidal, hyperbolic, and semi-hyperbolic, respectively.

(10) FIGS. 10A-10E depict examples of adjustable perimeter connectors.

(11) FIG. 11 is a detail view of a braided ligature.

(12) FIG. 12 is a perspective view of an embodiment in which the ligatures span the entire side-to-side length of the frame and serve functionally as both the ligatures and the mesh layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(13) Referring to FIGS. 4-7, the device 10 for absorbing and dissipating the energy of a dropped or thrown object includes a flexible planar layer (mesh layer) 12, a frame 14 supporting the mesh layer 12, energy absorbing and dissipating elements (ligatures) 16 connecting the mesh layer 12 to the frame 14, and a void space 18 between the mesh layer 12 and a surface 20 on which the frame 14 rests, for example a floor, foundation, or wall.

(14) The mesh layer 12 is directly impacted and deflected downwards by the falling or thrown weight and transfers a portion of the kinetic energy and the impact force to the frame 14 through the ligatures 16. Friction between the deforming components of the mesh layer 12 contributes to the kinetic energy dissipation. The mesh layer 12 may be woven or non-woven, and made from strong, tough, abrasion resistant, and flexible materials including, but not limited to, woven nylon webbing, aramid fiber cloth, woven rope, non-woven polyester, nylon, or polypropylene, and metallic fabrics of steel or aluminum mesh. In some embodiments, the mesh layer 12 may include a textured or coated surface for enhanced friction between the weavings of the mesh layer 12 to increase frictional energy dissipation of the falling weight.

(15) The ligatures 16 elongate in tension when the mesh layer 12 is deflected by a falling or thrown weight. Tensile deformation increases the efficiency of energy absorption and dissipation, since the full volume of the material is deformed, and multiple ligatures are activated. In contrast, current commercial gym mats made of rubber and foam are used in compression, which only deforms a small volume of material directly under and immediately adjacent to the weight.

(16) Preferably, the ligatures 16 are composed of viscoelastic materials that dissipate stored strain energy through internal friction mechanisms, converting a portion of the kinetic energy of the falling or thrown weight into waste heat.

(17) The ligatures 16 can be made of various materials, such as a range of filled and unfilled rubber (e.g., butyl, polyisoprene, etc), polyurethane, Sorbothane, and thermoplastic elastomers or other suitable materials with energy absorbing and dissipating properties. In one embodiment, paraffin was diffused into cured butyl rubber at 100 C. resulting in a 50% reduction of rebound or bounce and no ringing after the first rebound, compared to untreated butyl rubber. Further, the diffusion time and paraffin molecular weight could be controlled to tailor the energy dissipation during an impact cycle.

(18) The ligatures 16 can be made in various shapes, configurations, and combinations of configurations, including, but not limited to single strands of material, braided strands (FIG. 11), loops, or a semi-continuous, or a continuous element that serves many attachment points. The ligatures 16 can be attached to the mesh layer 12 by various mesh connections 13, comprising direct attachment by knots or weaving, S-hooks, D-Rings, eyelets, grommets, and/or hook-and-loop straps. The ligatures 16 can be attached to the frame 14 by multiple perimeter connectors 15, comprising bolts, screws, rivets, clamps, snaps, hook-and-loop straps, and/or adhesives. The ligatures 16 can also be directly attached to the frame 14 by multiple perimeter connectors 15, comprising apertures, notches, grooves, channels, flanges and/or protrusions of the frame 14.

(19) Different embodiments of the device 10 will potentially use different types, numbers, and distributions of ligatures 16 to control the amount of deflection of the mesh layer 12 and minimize the rebound or bounce of the weight depending on the weight, drop height, or thrown trajectory range anticipated. A greater number and greater local concentration of ligatures 16, may be required for heavier weights, larger drop heights, or thrown trajectories for a particular frame geometry.

(20) In some embodiments, the ligatures 16 may have adjustable tension, allowing the user to control the deflection of the mesh layer 12 and further tailor the performance of the device 10 to specific weight ranges, impact drop heights, or thrown trajectories. Greater tension in the ligatures 16 creates greater tension in the mesh layer 12 and reduces the deflection for a given weight, drop height, or thrown trajectory. As depicted in FIGS. 9A-9E, various methods, and combinations of methods, to adjust the tension comprise adjustable hooks and eyes, adjustable clamps, adjustable screws, adjustable tension cables, adjustable loop and pins, and adjustable hook-and-loop straps.

(21) The length, number, and distribution of ligatures 16 can be varied according to the specific application conditions. As depicted in FIG. 12, one embodiment 10A uses ligatures 16 that span the entire distance from one side of the frame 14 to the other in various configurations, number, distribution, and tension. Alternatively, it is possible to use a single continuous ligature 16 to create a woven configuration. In both of these embodiments, the ligatures 16 become the functional mesh layer 12. In another embodiment 10C, as shown in FIG. 7, multiple mesh layers 12 may be used and attached to the frame 14 using independent ligatures or the same ligatures 16.

(22) The frame 14 provides support for the mesh layer 12 and transfers the remaining portion of the kinetic energy and the reduced impact force to the surface 20 on which the frame rests. The frame 14 can be made of various materials, including but not limited to, steel, aluminum, titanium, magnesium, and other metals, polycarbonate, ABS, polypropylene, and other polymer materials, class and carbon fiber composite materials, cellular and honeycomb materials, and natural materials, including wood and bamboo, depending on the weight, drop height, or thrown trajectory range required. The frame 14 using these, and other materials can be fabricated by welding, casting, extrusion, injection molding, compression molding, and cutting, shaping, and molding.

(23) The frame 14 height and width can be designed to be greater or lesser depending on the weight, drop height, and thrown trajectory range. Greater weights, higher drop heights, and more aggressive thrown trajectories typically require a higher and thicker frame to withstand the kinetic energy and forces generated in the frame 14, spread the reduced impact force over a greater surface area, and to prevent the weight and the mesh layer 12 from contacting the floor.

(24) As illustrated in FIGS. 8A-8G, the frame 14 can incorporate different shapes, comprising arc, chord, Figure-8, oval, rectangle, polygon, circle, ellipse, and/or combination shapes. The distance between opposite sides of the frame 14 is an important design factor to control the deflection of the mesh layer 12. Longer distances result in greater deflection. The deflection of the flexible planar layer 12 can also be controlled by the type, number, distribution and tension of the ligatures 16. As illustrated in FIGS. 9A-9E, the frame 14 may also have a trapezoidal or other suitably shaped cross-section to increase the contact area with the surface 20, thereby further distributing the remaining kinetic energy and force and reducing sound and vibration transmission.

(25) An example embodiment of the device 10 is illustrated in FIGS. 1-3. The figure-8 frame 14 shape reduces both the distance between the opposing sides of the frame 14 and allows a greater radial distribution of the impact force to deform more ligatures 16. In designing the frame, the maximum magnitude of the deflection of the weight and mesh layer 12 scales non-linearly with the distance between opposing sides of the frame. Doubling the distance results in an increase in the deflection more than simply double. For example, in the case of linear-elastic materials and small deflections, the maximum deflection of a simply supported beam with uniform loading scales with the beam length to the fourth power. Doubling the length results in a maximum deflection eight times greater. For non-linear materials, such as rubber, and large deformations, the maximum deformation is expected to be even larger than the linear-elastic case as a function of the length. Therefore, shorter distances between opposing sides of the frame 14 is a powerful design variable to more easily prevent the weight and mesh layer 12 from impacting the surface 20 directly for the same number, distribution, and tension of energy absorbing and dissipating elements 12.

(26) The mesh layer 12 in this embodiment is a single layer of woven nylon webbing material. The woven nylon webbing was demonstrated to reduce the rebound or bounce of the weight, compared to, for example, woven polypropylene rope, due possibly to both the more rigid structure of the woven nylon webbing causing more of the ligatures 16 to be elongated and the increased frictional interaction between the nylon webs contributing to the energy dissipation.

(27) The mesh layer 12 in this embodiment is attached to the frame 14 by using a continuous braided paraffin-treated butyl rubber ligature 16. The paraffin treated butyl rubber was used because of its noted excellent energy absorption and dissipation properties and a braid was used to increase the friction between the braided rubber strands and add to the energy dissipation and reduction of the rebound or bounce of the weight. The energy ligature 16 is woven into the ends of the nylon webbing and attached to the frame 12 by looping around multiple bolt-like protrusions 15 mounted into the frame 12.

(28) The void space 18 between the mesh layer 12 and the surface 20 allows for the falling weight or thrown weight to decelerate over a greater distance and time, thereby reducing the total force applied to the frame 14 and the surface 20. The reduced force results in reduced sound and vibration transmitted to the surface 20.

(29) In operation, the falling or thrown weight contacts and deflects the mesh layer 12, causing the ligatures 16 to elongate in tension and absorb and dissipate a portion of the kinetic energy of the weight. Also, the friction between the deforming elements of the mesh layer 12 contributes to the kinetic energy dissipation. The remaining kinetic energy is transferred to the frame 14. The void-space 18 allows the falling weight to decelerate over a greater distance and time, thereby reducing the total kinetic energy and dynamic force applied to the frame and the supporting surface 20 on which the frame rests. The frame 14 contact area is large, distributing the reduced impact force over a greater physical contact area, contributing to greatly reduced sound transmission. The device prevents the weight and supporting mesh layer 12 from directly contacting the supporting surface 20. The impact energy is dissipated through the extension and contraction of the ligatures 16 resulting in reduced bounce of the weight.

(30) The device 10 is suitable for use in various environments requiring reduced impact force and sound and vibration transmission, such as home gyms, commercial gyms, and fitness settings as well as other environments where impact is present. The device 10 can be used for weightlifting with dumbbells, kettle bells, and barbells, wall-mounted impactors, CrossFit, or high-intensity interval training (HIIT) exercises that may involve dropping or throwing weights.

(31) The invention provides several advantages over conventional gym mats, including more effective reduction of impact force and sound and vibration transmission, reduced bounce of weights upon impact, improved user safety, and reduced damage to floors, foundations, and walls.

(32) In conclusion, the present invention provides a device for absorbing and dissipating the energy of a dropped or thrown object and reducing impact force and sound and vibration transmission. The device includes a mesh layer 12, energy-absorbing and dissipating ligatures 16, a frame 14, and a void space 18 between the frame 14 and the surface 20 on which the frame 14 rests, for example a floor, foundation, or wall. The mesh layer 12 is connected to a frame by energy absorbing and dissipating ligatures 16, and the void space 20 allows the falling weight to decelerate over a greater distance and time, thereby reducing the total force applied to the frame 14 and the surface 20 on which the frame 14 rests. The invention provides improved sound and vibration transmission reduction, increased user safety, and reduced damage to floors, foundations, and walls.

(33) Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that many additions, modifications and substitutions are possible, without departing from the scope and spirit of the present invention as defined by the accompanying claims.