WO2016118115A1

WO2016118115A1 - Monorail system

Info

Publication number: WO2016118115A1
Application number: PCT/US2015/012042
Authority: WO
Inventors: Nathan Milton SARGENT; Kynan Dee WYNNE; Tyson Matheson MUNFORD; Joshua Paul ADAM; Braxton Tyler SCHINDLER
Original assignee: Rooftop Anchor, Inc
Priority date: 2015-01-20
Filing date: 2015-01-20
Publication date: 2016-07-28

Abstract

A suspended access device including a trolley with a body, multiple axles through the body, each axle having a wheel on either side of the body and a monorail that includes a pair of flanges separated such a part of the body of the trolley fits between the flanges with a wheel of a first axle resting on each flange such that the load on the trolley is borne only by the wheels mounted to the first axle.

Description

MONORAIL SYSTEM

BACKGROUND

[0001] People working on the tops and sides of buildings, as well as other high structures risk falling and suffering injury as a result. In modern society, building maintenance is an area that continues to expose workers to the risk of dangerous falls. Accordingly to the U.S. Department of Labor, work related falls are among the most common sources of work related severe injuries and death. (See, e.g., https://www.osha.gov/SLTC/fallprotection/). The Department of Labor's Bureau of Labor Statistics reports that slips, trips and falls resulted in approximately 229,000 injuries per year (201 1-2013) resulting in approximately 700 workplace deaths per year. Death from falls is second only to vehicle related deaths and account for roughly 16% of work related deaths.

OSHA and ANSI 1-14 provide standards to reduce the number and severity of workplace falls. Fall protection equipment must perform under a wide variety of conditions while not hindering the ability of workers to safely perform their jobs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The accompanying drawings illustrate various examples of the principles described herein and are a part of the specification. The illustrated examples are given merely for illustration, and do not limit the scope of the claims.

[0003] Fig. 1 is a perspective view of a monorail system depicting a cut away view of a monorail and a trolley coupled thereto, according to one example of the principles described herein.

[0004] Fig. 2 is a side view of a trolley of the monorail system of Fig. 1 depicting a two-wheels-up-one-wheel-down wheel arrangement, according to another example of the principles described herein.

[0005] Fig. 3 is a side cut-away view of the monorail system of Fig. 1 depicting a profile of the monorail and a front view of the trolley including a one- 5 wheel-up-two-wheels-down wheel arrangement as depicted in Fig. 5, according to one example of the principles described herein.

[0006] Fig. 4 is a top view of the trolley depicting a two-wheels-up-one- wheel-down wheel arrangement, according to one example of the principles described herein.

10 [0007] Fig. 5 is a side view of a trolley of the monorail system depicting the trolley including a one-wheel-up-two-wheels-down wheel arrangement as depicted in Fig. 1 , according to another example of the principles described herein.

[0008] Fig. 6 is an orthogonal view of the trolley depicting a two-wheels- i s up-one-wheel-down wheel arrangement of Fig. 2, according to one example of the principles described herein.

[0009] Fig. 7 is an orthogonal view of the trolley depicting a one-wheel- up-two-wheels-down wheel arrangement of Fig. 5, according to one example of the principles described herein.

20 [0010] Fig. 8 is a cross-sectional front view of the monorail system with a trolley under a load, according to one example of the principles described herein.

[0011] Fig. 9 is a cross-sectional front view of the monorail system with a trolley under a side load, according to one example of the principles described 25 herein.

[0012] Figs. 10A and 10B are cross sectional views of mounting configurations for portions of the monorail of Fig. 3, according two examples of the principles described herein.

[0013] Fig. 1 1 depicts a top view of a trolley traveling through a curve 30 section of monorail, according to an examples of the principles described

herein.

[0014] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. DETAILED DESCRIPTION OF THE DRAWINGS

[0015] In order to access some areas of buildings such as under overhangs, special equipment and systems may be required. Rope access technicians use climbing and abseiling techniques and this specialized equipment in order to access difficult-to-reach areas from above for various industrial applications like maintenance, construction, inspection, and welding. While close to the ground, lifts and ladders may be options; at certain heights, they become impractical. To access such areas, specialized suspension access devices such as harnesses, ropes, rail systems, davit systems, and outrigger beams may be used. These and other devices support workers as they perform their work, and may share features with fall protection systems and similarly function to reduce the number and injuries resulting from falls.

However, while a fall protection system may be focused on the impact of a fall by a worker and their equipment, they generally are not load bearing devices designed to continuously support a worker and equipment.

[0016] Like an airbag, bike helmet, or other piece of safety equipment, a fall protection device may be designed to absorb an impact in a way that renders it unsafe or unusable subsequently. This may include deformable parts that are designed to bend or break to direct the energy of the impact. During normal use, such safety devices may include minimal loads placed on them, for instance to reduce the force to move them around with the worker. In contrast, a system for suspending a worker may need to continuously and safely support the weight of the worker and associated equipment while being capable of dealing with impacts from falls or other unexpected events without deforming or breaking.

[0017] Thus, examples described herein provide a body, the body having a number of axles running through it. The axle includes a wheel mounted on each side of the body. The wheels rest upon portions of a monorail. The monorail attached, either directly or indirectly to a surface so as to provide access to a work area for a worker suspended from the body.

[0018] In another example, the device may further include a second axle with a wheel mounted on one side of the body. The wheel is chamfered on the outer diameter away from the body. The wheel contacts the monorail on the chamfer only, which prevents or reduces binding when tangential loads are applied to the body. In some examples, the second axle includes a wheel on each side of the body, both chamfered on the outer diameter away from the body. The chamfered areas on both wheels of the second axle serving as their only contact with the monorail. In yet another example, there are two or more upper axles each with chamfered wheels.

[0019] The following describes a trolley and monorail system to reduce injuries from falls for people working at height. The worker is secured to the trolley, which moves with the worker by running along the monorail.

[0020] As used in the present specification and in the appended claims, the term "a number of" or similar language is meant to be understood broadly as any positive number comprising 1 to infinity; zero not being a number, but the absence of a number.

[0021] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present systems and methods. It will be apparent, however, to one skilled in the art that the present apparatus, systems, and methods may be practiced without these specific details. Reference in the specification to "an example" or similar language means that a particular feature, structure, or characteristic described in connection with that example is included as described, but may not be included in other examples.

[0022] Turning now to the figures, Fig. 1 is a perspective view of a monorail system (100) depicting a cut away view of a monorail (101 ) and a trolley (102) coupled thereto, according to one example of the principles described herein. The monorail system (100) may be coupled to any portion of a building. In one example, the monorail system (100) may be coupled to the bottom of an overhang or other structure that protrudes from a building. The various elements of the monorail system (100) may be made of materials that are not subjected to weather and environmental contaminates. In one example, the monorail system (100) may be made of metals such as, for example, steel, aluminum, and titanium. In another example, the monorail system (100) may be made of composites such as, for example, carbon fiber structures, and fiberglass. In still another example, the monorail system (100) may be made of structural polymers such as, for example, polycarbonate, polyurethane, and polyether ether ketone. In yet another example, the monorail system (100) may be made of natural materials such as woods.

[0023] The monorail system (100) includes a monorail (101 ) and a trolley (102). At least a portion of the trolley (102) is housed within the monorail (101 ), and is restrained by the monorail (101 ) except in the directions indicated by arrow 103. In this manner, the trolley (102) may be used as an anchor from which a user may hang, abseil, or climb in order to access difficult-to-reach areas such as portions of the building under an overhang or along the side of the building. Although a short section of monorail (101 ) is depicted in Fig. 1 , the length of the monorail (101 ), and, in turn, the travel of the trolley (102) may be as long as the width of the structure to which the monorail system (100) is coupled or longer. In one example, the length of monorail (101 ) may be custom based on a desired application. In another example, the length of monorail (101 ) may be defined by a user's desire to access a number of portions of the structure via the monorail system (100). Details regarding the monorail (101 ) and the trolley (102) will now be described in more detail.

[0024] Fig. 2 is a side view of a trolley of the monorail system of Fig. 1 depicting a two-wheels-up-one-wheel-down wheel arrangement, according to one example of the principles described herein. Fig. 3 is a side cut-away view of the monorail system of Fig. 1 depicting a profile of the monorail (101 ) and a front view of the trolley (102) including a one-wheel-up-two-wheels-down wheel arrangement as depicted in Fig. 5, according to one example of the principles described herein. The trolley (102) includes a body (1 10) with at least two axles, collectively referred to using reference numeral 120. In one example, the trolley (102) may comprise three axles (120-1 , 120-2, 120-3). Each axle (120- 1 , 120-2, 120—3) includes a pair of wheels (130) wherein one wheel is attached to the axle (120) on either side of the body (110).

[0025] Fig. 2 depicts a trolley (102) including a two-up-one-down arrangement of axles (120-1 , 120-2, 120-3) and wheels (130). In other examples described herein, the trolley (102) may include a one-up-two-down arrangement of axles (120-1 , 120-2, 120-3) and wheels (130) as depicted in, for example, Fig. 5. As will be described herein, at least one axle (120-1 , 120-2, 120-3) includes a pair of wheels (130) which rest on a pair of lower support flanges (Fig. 3, 280) that support the trolley (102) and any personnel or equipment attached to the trolley (102). A number of additional axles (120-1 , 120-2, 120-3) may be located horizontally higher relative to the at least one axle. These additional axles (120-1 , 120-2, 120-3) include at least one wheel (130). The wheel (130) of the additional axles (120-1 , 120-2, 120-3) do not contact the lower support flanges (Fig. 3, 280) and do not support the trolley (102).

[0026] The trolley (102) is designed to support a suspended load. The weight is transferred from the body (1 10) of the trolley (102) through the axles (120) and wheels (130) to the lower support flanges (Fig. 3, 280) of the monorail (101 ), the monorail being secured to a surface of the structure to which the monorail system is to be coupled. The trolley (102) rolls along the lower support flanges (Fig. 3, 280) and the slot between the lower support flanges (Fig. 3, 280). A portion of the trolley (102) extends below the monorail to facilitate attachment of fall protection and suspended access equipment such as harnesses and ropes.

[0027] The body (1 10) of the trolley (102) transfers load from a worker or equipment through the axles (120) and wheels (130) of a number of lower axles (120) to the lower support flanges (Fig. 3, 280) and eventually to the building or surface. A variety of materials may provide the desired properties for the body (110). These materials include, for example: metals such as, for example, steel, aluminum, and titanium; composites such as, for example, carbon fiber structures and fiberglass; structural polymers such as, for example,

polycarbonate, polyurethane, and polyether ether ketone; and natural materials such as woods. The body (110) may include a structural skeleton with a molded, cast, and/or attached form to facilitate handling or support of workers or equipment. [0028] The body (1 10) includes a portion that extends through the slot between the lower support flanges (Fig. 3, 280) to allow attachment of equipment or personnel. This portion may include a number of apertures defined in the body (1 10); the apertures being collectively referred to using reference numeral 140. Thus, the body (1 10) may include multiple apertures in the body (1 10) including a main aperture (140-1 ) and a number of auxiliary apertures (140-2, 140-3).

[0029] While a number of different mechanisms may be used to secure items and workers to the trolley, the use of apertures provides a number of benefits. First, the apertures (140) are simple in design providing for a wide variety of equipment and securement devices to be used the trolley (102). This provides flexibility in the utility of the trolley (102). Second, the apertures (140) do not include small or fragile parts vulnerable to damage during use or from exposure to the elements. Third, the apertures (140) do not include sharp edges that may injure workers.

[0030] One aspect of the apertures (240) is the inclusion of more than one aperture (240) such that one may be used to hold a piece of equipment and another may be used to secure a worker. The apertures (240) may be round or may include elements to limit or control rotation of the secured item. The present specification discloses a large aperture (240) capable of receiving ropes or other large elements for suspension. In one example, the aperture is larger in one dimension than the diameter of a wheel used on the trolley.

[0031] The axles (120) transfer a load from the body (1 10) to the wheels (130). The axles (120) also facilitate rotation of the wheels (130). In one example, the axles (120) may rotate with respect to the body (1 10). In another example, the axles (120) may be fixed with respect to the body (110). Similarly, in one example, the wheels (130) may rotate with respect to the axles (120). In another example, the wheels (130) may be fixed with respect to the axle (120). On another example, the wheels (130) of an axle (120) may rotate

independently of each other.

[0032] In one example, the body (1 10) includes a ball bearing to facilitate rotation of the axles (120) with respect to the body (1 10). In another example, ball bearings are located between the axles (120) and the wheels (130). This example allows the wheels (130) to rotate independently of each other and distributes the load over two bearings rather than a single bearing.

[0033] In one example, the axle (120) may be of relatively constant diameter. In another example, the axle (120) may be larger where it passes through the body (1 10) and smaller in the portion where the wheels (130) are mounted. In one example, the portion of the body (110) at which the axles (120) are mounted may include a non-circular cross section to prevent rotation or facilitate assembly. In another example, the portion of the body (1 10) at which the axles (120) are mounted may include a locking pin or similar attachment mechanism to prevent rotation. The portion of the body (110) at which the axles (120) are mounted may be threaded, partially threaded, grooved, or otherwise provided with features to facilitate assembly and disassembly of the trolley (102). The axle (120) may include a lock nut between the body (1 10) and the wheel (130) to assist in holding the axle (120) in place. The axle (120) may be made of any suitable material, including, for instance: steel, aluminum, and titanium.

[0034] The wheels (130) are mounted to the axles (120), and, during use the wheels of (130) the number of lower axles (120), rest on the lower support flanges (Fig. 3, 280). The wheels (130) rotate to facilitate motion of the trolley (102) along the support flanges (Fig. 3, 280) and the length of the monorail (101 ). The wheels (130) may be composed of a variety of different materials including: metals, polymers, composites, and natural materials. In one example, the wheels (130) are a polyurethane (PU), polycarbonate (PC), polyether ether ketone (PEEK) or a similar materials and composites. The wheels (130) may be protected from the elements and ultraviolet (UV) radiation exposure by virtue of the cross section of the monorail (101 ) including an enclosed cross section. This allows a wide variety of materials to be used as the wheels (130). Because the trolley (102) may sit statically for extended periods, the wheels (130) may be manufactured from a material that is not prone to remodeling or flow.

[0035] In one example, the wheels (130) may be of a single size and design so as to reduce the number of different parts stored in inventory, and to reduce manufacturing costs associated with desperate parts. In another example, the wheels (130) may be formed with different diameters, widths, and geometries or made of different materials. In one example, the wheels (130) include a chamfer (Fig. 2, 150) on one side of the outer diameter while the other side of the outer diameter is approximately square. This design allows the upper wheels (130) to use the chamfer as a running surface while maximizing the contact area between the lower wheels (130) and the support flanges (Fig. 3, 280) using a single wheel (130) design.

[0036] In one example, the wheels (130) may include a bearing on the inner diameter, with the wheel (130) being attached to the bearing using adhesive or by casting the wheels (130) over the bearing. The outer surface of the bearing may include a protrusion or indent to provide mechanical interlock between the wheel (130) and bearing. Similarly, the axle (120) may include a feature to provide mechanical interlock between the bearing and the axle (120).

[0037] In some examples, the gap between the side of the wheel (130) and the body (1 10) is small so as to limit the ability of material to get into the bearings. In this example, the gap between the side of the wheel (130) and the body (1 10) is less than 0.25 inches. This also includes the advantage of limiting the length of axle (120) between the body (110) and the wheel (130) where the axle (120) is unsupported resulting in the axle being relatively robust and structurally rigid than if the axle were longer. This also may include the advantage of distributing the load of the trolley (102) over a wider area of the wheels (130) and the lower support flanges (Fig. 3, 280). Further, this design includes the potential advantage of reducing the bending moment on the axle (120).

[0038] The lower support flanges (Fig. 3, 280) are located to support the wheels (130) of the number of lower axles (120). A slot (301 ) defined between the lower support flanges (Fig. 3, 280) allows the body (110) to extend through the slot (301 ) and below the lower support flanges (Fig. 3, 280) where workers or equipment may be attached to the main aperture (Fig. 2, 140-1 ) of the body (110). A number of upper support flanges (290) are also included, and wheels (130) or the chamfered portion of the wheels (130) of an upper axle (120) may contact the upper support flanges (290) at interface (234) such that an interference fit is created between the profile of all the wheels (130) (both lower and upper wheels) and the vertical profile of the monorail (101 ). This may eliminate or reduce binding of the trolley (102) and facilitate smooth travel of the trolley (102) over the support flanges (Fig. 3, 280) and along the length of the monorail (101 ).

[0039] The lower support flanges (280) and upper support flanges (290) are formed from an integral structure with respect to the upper support flanges (290). The use of an integral structure for the flanges (280, 390) reduces the risk of failure and eliminates the need for bolts or similar elements to secure the components together.

[0040] In one example, the lower support flanges (280) are thicker than other portions of the monorail (101 ) such as, for example, the upper support flange (280). This greater thickness assists the lower support flanges (280) to resist bending under the weight of the trolley (102) and its load. In contrast, the bending moment on other portions of the integral structure may be lower, allowing thinner walls. In this manner, manufacturing and installation costs may be reduced by way of costs of materials and reduced weight of a length of monorail (101 ). Similarly, the area where the lower support flanges (280) connect to the remainder of the integral support structure may be thickened or reinforced to resist bending of the lower support flanges (280). The lower support flanges (280) may be connected to sections with similar cross section end to end to extend the length of the monorail (101 ) and the distance the trolley (102) may travel. These connections may include overlapping portions, bolts, pins, clasps, or similar elements to secure the lengths of monorail (101 ) together and provide for smooth and secure travel by the trolley (102) between sections of the monorail.

[0041] The monorail (101 ) may be made of sections attached end to end to form a longer travel length. The sections may include attachment points for a number of fastening devices. In one example, a number of keeper pin recesses (302) are defined within the monorail (101 ). In this example, a number of keeper pins may be inserted into the keeper pin recesses (302) to couple the lengths of monorail (101 ) to one another. In another example, adjacent sections of the monorail (101 ) are welded together. The ends of the monorail (101 ) sections may be flush. Alternately, the ends may include alignment features including pins, guides, openings, divots, hollows, protrusion, etc. to facilitate connection of the sections.

[0042] The support flanges (280, 390) may be produced from a variety of materials including, but not limited to: metals such as steel, aluminum, titanium, magnesium; polymers such as polycarbonate (PC), polyurethane (PU), and Polyether ether ketone (PEEK); and composites such as fiberglass. In one example, aluminum is used due to its combination of corrosion resistance, high strength, low weight, cost, and ease of drilling holes on site for mounting, among other advantageous qualities. Because of their vulnerability to environmental and UV exposure, polymers may be less suitable for certain applications but may be appropriate options for indoor or underground applications. Similarly, one material may be used for straight sections of the monorail while custom or specialty sections such as curves, exchanges, junctions, or similar structures may benefit from manufacture using a second material.

[0043] In one example, the contact surface of the support flanges (280, 390) includes a polymer or other coating to increase grip or friction between the support flanges (280, 390) and the wheels (130). In another example, the wheels (130) contacting surfaces of the support flanges (280, 390) include texturing to increase grip or friction between the support flanges (280, 390) and the wheels (130). While the lower support flanges (280) are approximately flat to facilitate smooth motion by the trolley (102), the inclusion of bumps, ridges, or other texture at various points may be included, for example, to signal position along the length of the monorail (101 ) to a user or to help the trolley (102) to stay in one place near a loading point. In one example, the support flanges (280, 390) are constructed from a single extrusion such that there may be fewer potential points of failure compared with designs made of multiple elements bolted together.

[0044] Side contact of the monorail (101 ) by the wheels (130) in the middle of the trolley (102) may decrease the radius of curvature that may be used in turns within the monorail system (100). If the trolley (102) includes side- contacting elements at multiple points in the direction perpendicular to the axles (120), then the radius of curvature is increased, or the body (110) may need to include a flexible joint, providing another potential point of failure. If such a joint is desired, the joint provides lateral bending while maintaining vertical rigidity and strength. Such a hinge style joint may include stops that limit the maximum bending angle between the pieces of the body (1 10).

[0045] The use of chamfered edge contact (234) in connection with the number of upper axles (120) and wheels (130), and the upper support flanges (290) provides protection against binding of the trolley (102). The upper wheel (130) chamfer (Fig. 2, 150) may serve as a contact point with the upper support flanges (290). When side loaded, the trolley (102) would still move on the number of lower wheels (130) on one side of the trolley (102) and the upper wheels (130) on one or both sides of the body (1 10). This prevents contact between the body (1 10) and the sides of the slot when a lateral load is applied to the trolley (102). As the imposition of a lateral load may occur because of an unanticipated event, the ability to move the trolley (102) under such conditions is a safety feature.

[0046] The wheels (130) of an upper axle contact the upper support flange (290) under normal operating conditions. The contact is restricted to the chamfer portion of the wheel. This decreases friction, and provides for functionality under lateral loading. The outer diameter of the wheels (130) on a number of upper axles (120) do not contact the top interior space (303) of the monorail (101 ). Instead, the outer diameter of the wheels (130) on a number of upper axles (120) contact the upper support flange (290); the sloped area on the side and top of the monorail (101 ).

[0047] Fig. 4 is a top view of the trolley depicting a two-wheels-up-one- wheel-down wheel arrangement, according to one example of the principles described herein. The body (1 10) of the trolley (102) is depicted with multiple axles (120). The wheels (130) with their chamfers (150) are also visible. The chamfers (150) are located on different sides of the wheel (130) with some facing the body (110) of the trolley (102) and some facing away from the body of the trolley (102). In one example, the wheels (130) of the number of upper axles (120) are mounted with the chamfer (150) away from the body (1 10) of the trolley (102) and the wheels of the lower axle or axles (120) are mounted with the chamfer (150) toward the body (110) of the trolley (102). In another example, the wheels (130) of the number of upper axles (120) may be mounted with the chamfer (150) toward the body (1 10) of the trolley (102) and the wheels of the lower axle or axles (120) may be mounted with the chamfer (150) away from the body (1 10) of the trolley (102).

[0048] Fig. 4 also depicts the use of non-uniform diameter axles (120) with a larger diameter in the body (1 10) and a smaller diameter in the wheels (130). In another example, the diameter of the axles (120) may be uniform along the length of the axles (120).

[0049] Fig. 5 is a side view of a trolley (102) of the monorail system (100) depicting the trolley (102) including a one-wheel-up-two-wheels-down wheel arrangement as depicted in Fig. 1 , according to another example of the principles described herein. In this example, the trolley (102) includes three axles (120-1 , 120-2, 120-3) with the wheels (130) of two axles (120-1 , 120-2) resting on the lower support flanges (Fig. 3, 280) and the wheel (130) of the third axle (120-3) contacting the upper support flange (Fig. 3, 290). The wheels (130) of the third axle (120-3) include a chamfer (150) on the outer diameter where they contact the upper support flange (Fig. 3, 290). The body (1 10) of the trolley (102) further includes a plurality of apertures (140) for suspending equipment and/or workers.

[0050] Fig. 6 is an orthogonal view of the trolley (102) depicting a two- wheels-up-one-wheel-down wheel arrangement of Fig. 1 and of the example of Fig. 2, according to one example of the principles described herein. The body (110) of the trolley (102) is visible with the wheels (130) mounted on the axles (120). The body (1 10) includes a number of apertures (140). The chamfers (150) of the upper wheels (130) are evident on the outer radius away from the body (1 10). In this example, the chamfers (150) of the lower wheels (130) are on the inner diameter of the lower wheels (130) toward the body (1 10). [0051] Fig. 7 is an orthogonal view of the trolley (102) depicting a one- wheel-up-two-wheels-down wheel arrangement of Fig. 1 and of the example of Fig. 5, according to one example of the principles described herein. The body (110) of the trolley (102) is visible with the wheels (130) mounted on the axles (120). The body (1 10) includes a number of apertures (140). An additional aperture (140-4) may be defined within the body (1 10) to save on materials used to manufacture the trolley (102). The chamfers (150) of the upper wheels (130) are evident on the outer radius away from the body (1 10). The chamfers (150) of the lower wheels (130) are on the outer diameter toward the body (1 10).

[0052] Fig. 8 is a cross-sectional front view of the monorail system (100) with a trolley (102) under a load (801 ), according to one example of the principles described herein. Fig. 9 is a cross-sectional front view of the monorail system (100) with a trolley (102) under a side load (802), according to one example of the principles described herein. Weight of objects attached to the body (1 10) of the trolley (102) is transferred through the lower axle (120) and wheels (130) to the lower support flanges (Fig. 3, 280). The lower support flanges (Fig. 3, 280) are part of the monorail. The monorail (101 ) is secured to a building or surface to allow access to a work site. The examples of the monorail system (100) provided herein eliminate or reduce binding of the trolley (102) and facilitate smooth travel of the trolley (102) over the support flanges (Fig. 3, 280) and along the length of the monorail (101 ).

[0053] As depicted in Fig. 9, the trolley (102) is designed so that when a lateral or side load is applied to the body (1 10), the body (1 10) does not contact the lower support flanges (Fig. 3, 280). Further, the trolley (102) continues to travel on its wheels (130) so that the force to move the trolley (102) along the monorail is similar to the force required under a load (801 ) orthogonal to the axles (120) of the trolley. As may be seen in Fig. 9, the application of a side or lateral load against the trolley (102) causes the load to be sharedwith the wheels (130) of the lower axle(s) (120) and upper axles (against the mid flange (290). The load (802) is then borne by the wheel (130) of the upper axle (120) on the side of the body (120) away from the load (802) and the wheel (130) of the lower axle (120) on the side of the body (110) toward the load (802). The other wheels (130) of both axles (120) may help support the load (802), but motion and vibration may cause them to slip while the two described wheels (130) will tend to carry a greater load under lateral loading conditions. The side load (802) applied to the trolley (102) does not disengage the interface (234) between the wheels (301 ) of axle (120-1 ) and the upper support flanges (290). Further, the side load (802) applied to the trolley (102) does not disengage the interface (232) between the wheels (301 ) of axle (120-3) and the lower support flanges (Fig. 3, 280). In this manner, side loads (802) do not bind the trolley (102) within the monorail (101 ).

[0054] For the three axle (120) trolley (102) designs, the described side loading (802) results in three points of contact between the monorail and the trolley (102). Three non-linear points of contact form a stable position, meaning there should not be rocking or similar motion unless the center of gravity for the load is moving with respect to the trolley (102).

[0055] Since side loading may be the result of an unexpected occurrence such as a shift in equipment or change in support, the ability for the trolley (102) to continue to function under those conditions provides the benefit of allowing the worker to be able to move with the trolley (102). This is a safety feature.

[0056] Figs. 10A and 10B are cross sectional views of mounting configurations for portions of the monorail (101 ) of Fig. 3, according to examples of the principles described herein. Specifically, Fig. 10A depicts mounting the system using a knife plate (1001 ) and Fig. 10B depicts mounting the system using a bracket (1051 ).

[0057] The monorail (101 ) and trolley (102) may be attached to a variety of artificial or natural structures. Multiple methods of mounting the system may be designed into the profile of the monorail (101 ). As shown in Fig. 10A, in one example, the monorail (101 ) is mounted to a knife plate (1001 ) connected to a structure. The knife plate (1001 ) enters a channel (1002) defined in the monorail (101 ) opposite the slot (301 ) used by the trolley (102). Holes may be predrilled in the knife plate (1001 ) and the monorail (101 ), or the holes may be drilled on site during installation. Fastening devices (1003) are passed through the holes to secure the monorail (101 ) to the knife plate (1001 ). This may be accomplished with pins, bolts, nuts, washers, clamps, adhesives, or other types of fastening devices. Once installed, the load of the monorail (101 ) is transferred to the knife plate (1001 ) through the fastening devices (1003). In this manner, the load is centered under the knife plate (1001 ).

[0058] The monorail (101 ) includes an integral, central rib (1004) connecting the two sides of the monorail (101 ) beneath the fastening device (103). As a result, there is no lateral tensile stress on the fastening devices (1003). The force of gravity applied to the trolley (102) will push downward on the lower support flanges (Fig. 3, 280). This will apply a force to cause the lower support flanges (Fig. 3, 280) to bend down and away from each other. The central rib (1004) acts as a fulcrum resulting in compressive force being applied at the site of securement. This force is less likely to dislodge the bolts than a tensile load that would exist absent the central rib (1004). In the example of Fig. 10A, a first mounting flange (1020) and a second mounting flange (1021 ) may be used to provide support to the monorail (101 ) in directions indicated by arrow 1006 if a portion of the structure (1005) were abutting the first mounting flange (1020) or second mounting flange (1021 ) on either side of the knife plate (1001 ). However, the knife plate (1001 ) being coupled to the monorail (101 ) via the channel (1002) and the fastening devices (1003) provides enough support in the directions indicated by arrow 1006.

[0059] In one example, the monorail (101 ) may include divots, marking, indentations, or other features. These features may facilitate drilling the holes for securement, aid alignment of the pieces, and/or allow adjustment between segments. In one example, the monorail (101 ) is composed of a material that is relatively easy to drill holes on site, such as aluminum.

[0060] Fig. 10B depicts the mounting of the monorail (101 ) to a bracket

(1051 ) , according to one example of the principles described herein. The bracket (1051 ) may be mounted to a structure. Holes may be provided or drilled through the mounting flanges (1020, 1021 ) into the bracket. Fastening devices

(1052) may be used to secure the bracket (1051 ) to the monorail (101 ). Since the primary load is in the direction of the long axis of the fastening devices (1052), there is greater force applied to the fastening devices (1052). In some examples, bolts or similar fasteners are applied on both sides of the monorail between support flanges and the mounting bracket to provide redundancy in the connection.

[0061] In another example, the monorail (101 ) may also be mounted directly to a structure without the use of a bracket (1051 ) or knife plate (1001 ). This may use one or more of the mounting flanges (1020, 1021 ) coupled using a number of fastening devices.

[0062] Fig. 1 1 depicts a top view of a trolley traveling through a curve section of monorail, according to an examples of the principles described herein. The interior width dimensions of the cavity of the monorail (101 ) are shown by interior lines (1 162, 1164, 1 166) corresponding to the width of the level of an upper axle of the trolley (102) and the next line corresponding to the width at the level of the lower axle. Turn radius is a function of the separation of the trolley (102) to the sidewalls of the monorail (101 ) interior cavity. Where the trolley (102) includes multiple axles (120), the separation of the axles (120) in the direction of the lower support flanges (Fig. 3, 280) also affects the turn radius.

[0063] A rigid trolley (102) of a given length with a single axle (120) with wheels (130) contacting the side walls of the monorail (101 ) may include a better turn radius than a trolley (102) with multiple axles (120) with wheels (130) contacting or near to the side walls. If a single axle (120) with wheels (130) contacting the sidewalls is located in the center of the trolley (102), the trolley (102) will tend to include a tighter turning radius than if the axle (120) is located on the end of the trolley (120). If the contacting wheels (130) contact the monorail (101 ) on a chamfer (Fig. 2, 150), rather than a flush wall, the turning radius will tend to be improved as the chamfer (Fig. 2, 150) will prevent undesired contact between the leading edge of the wheel (130) and the side wall and the trailing edge and the opposite side wall. Accordingly, a design that uses a single axle (120) with sidewall contacting wheels (130) located near the center of the trolley (102), in the direction of travel, orthogonal to the axles (120), and parallel to the lower support flanges (Fig. 3, 280) will include a tighter turning radius compared with other examples.

[0064] As depicted in Fig. 1 1 , a trolley (102) with two lower axles (120) and a center upper axle (120) may make a turn that may not be made by a similarly sized trolley (102) with two upper axles (120) and a center lower axle (120). As discussed above, sidewall contact provides the benefit under side loading. Accordingly, it may not be desirable or feasible to eliminate sidewall contact by making the interior dimensions of the monorail (101 ) wider or the trolley narrower.

[0065] The specification and figures describe a system, device, and trolley for suspended access. The system may use a single load-bearing axle coupled with an additional axle. The system may include multiple apertures include a large aperture for connecting equipment and personnel. The system may include a single axle with wheels in contact with side portions of the monorail. This suspended access system, device, and trolley may include a number of advantages, including: reduced friction, the ability to accommodate equipment and personnel with separate connections, the ability to

accommodate multiple pieces of equipment simultaneously, tighter radius of curvature, and the ability to function under side load without contact between the body and the monorail.

[0066] The preceding description is presented to illustrate and define examples of the principles described herein. This description is not intended to be exhaustive or to limit these principles to any precise form disclosed. Many modifications and variations are possible in light of the above teaching.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A monorail system comprising:

a trolley comprising:

a body;

a plurality of axles mounted through the body and orthogonal to the body; and

a pair of wheels mounted on each axle, such that one wheel is located on each side of the body; and

a monorail comprising:

a pair of lower flanges running parallel to each other and separated such that a portion of the body of the trolley fits between the pair of lower flanges and a wheel from each side of a first axle of the plurality of axles rests on each of the pair of lower flanges,

wherein, when the trolley is mounted on the pair of lower flanges, a load applied to the trolley is borne only by wheels mounted to a first axle.

2. The monorail system of claim 1 , further comprising a flexible guard coupled between the pair of lower flanges to reduce contamination.

3. The monorail system of claim 1 , wherein the monorail further comprises an opening sized to allow the trolley to be inserted and removed through the opening.

4. The monorail system of claim 1 , wherein the body further comprises a plurality of apertures defined in the body for attaching objects to be supported by the fall protection device.

5. The monorail system of claim 1 , wherein the monorail further comprises a number of mounting flanges, each mounting flange comprising at least one surface parallel to the surfaces of the pair of lower flanges, the mounting flange being formed from the same piece of material as the flange.

6. The monorail system of claim 5, wherein the monorail further comprises a groove opposite the slot, the groove sized to accommodate a knife plate via which the fall protection device is coupled to a building.

7. The monorail system of claim 1 , wherein the monorail further comprises an upper flanged coupled to and running in the same direction as the pair of lower support flanges, both the pair of lower flanges and the upper flange forming a single enclosure,

wherein the upper flange is separated from the lower support flanges such that both wheels from at least one second axle are in contact with the upper flange and the lower flanges are thicker than the upper flange.

8. The monorail system of claim 7, wherein the wheels of a second axle and the wheels of the first axle form an interference fit between the upper and lower flanges of the monorail.

9. The monorail system of claim 1 , wherein the monorail is mounted to a building.

10. The monorail system of claim 1 , wherein the monorail is mounted to a bracket and the bracket is mounted to a building.

1 1. The monorail system of claim 1 , wherein the monorail comprises a plurality of segments connected to form continuous flanges, the segments secured together with a number of keeper pins.

12. A suspended access system for supporting a worker at heights, the system comprising:

a structure elongated in a first direction, the structure comprising:

an interior space elongated in the first direction, and a slot extending in the first direction;

a trolley to travel along the slot, the trolley comprising:

a body dimensioned to pass through the slot, a portion of the body within the interior space and a portion of the body external to the interior space;

a plurality of axles mounted orthogonal to the body through the portion of the body within the interior space, the axles being longer than a width of the slot; and

a plurality of pairs of wheels, each pair mounted on an axle with one wheel of the pair on either side of the body,

wherein both wheels on an upper axle are chamfered on an outer corner away from the body, the chamfered area of the wheel being the only portions of the upper wheels to contact a surface of the interior space upper flange and both wheels of a lower axle contact a surface of the interior space, one wheel on either side of the slot.

13. The suspended access system of claim 12 wherein the structure includes a mounting flange and a groove for receiving a projection, wherein the groove or the mounting flange couple the structure to a building.

14. The suspended access system of claim 12, further comprising a plurality of apertures defined in the portion of the body external to the interior space to support a load applied to the system.

15. The suspended access system of claim 12, wherein the structure further comprises a bushing in the slot to reduce contamination.

16. The suspended access system of claim 12, wherein side contact by the trolley is limited to the center of the trolley so as to minimize the turning radius of the trolley.

17. The suspended access system of claim 16, wherein the wheels of the upper axle and the wheels of the lower axle form a vertical compression fit between the upper support flange and the lower support flanges and the wheels of only one axle are proximal to the sides of the monorail and all other wheels are separated from the sides of the monorail.

18 The suspended access system of claim 17 wherein the only one axle is located between two other axles in the direction of travel of the trolley.

19. A trolley for supporting workers when working at heights, the trolley comprising:

a body;

a lower axle mounted orthogonally through the body;

a pair of wheels mounted to the axle such that one wheel is on each side of the body; and

a first aperture defined in the body, the first aperture being larger in a dimension than a diameter of a wheel of the pair of wheels, the first aperture allowing the connection of suspension devices to the trolley.

20. The trolley of claim 19, further comprising a second aperture defined in the body, the second aperture being dimensioned to accommodate attachment of fall protection equipment.

21. The trolley of claim 19, wherein a diameter of the lower axle in the body is larger than a diameter of the lower axle in a wheel of the pair of wheels.

22. The trolley of claim 19, further comprising an upper axle, the upper axle located above the lower axle, the upper axle comprising a pair of wheels mounted to the upper axle with one wheel on either side of the body, the wheels of the upper axles being chamfered on the outer diameter away from the body.

23. The trolley of claim 19, further comprising a plurality of lower axles, the lower axles located below the upper axles, each lower axle comprising a pair of wheels mounted to the lower axle with one wheel on either side of the body, the wheels of the lower axles being chamfered on the inner diameter towards the body, wherein the lower axles support the weight of a suspended user.