Cable tray hold-down

The present disclosure is related to a hold-down for a cable tray. The hold-down may be configured for high-wind situations. The hold-down includes a support clamp for clamping onto a support, and a hold-down arm for holding the cable tray on the support.

FIELD OF THE DISCLOSURE

The present disclosure is related to a hold-down for a cable tray.

BACKGROUND OF THE DISCLOSURE

A cable tray is typically supported by a series of parallel supports (e.g., struts, C-Channel, I-beams, etc.) suspended at intervals and spaced lengthwise of the cable tray. The cable tray rests on these supports and is held in position on the supports by hold-downs which are affixed to the supports. These hold-downs are intended to retain the cable tray on the supports and to inhibit lateral shifting of the cable tray relative to the supports. Two types of hold-down members are common in the industry: one type acting as a clamp for rigidly clamping a cable tray against a corresponding support; and a second type acting as a guide which holds the cable tray loosely on the support to permit thermal expansion and contraction of the cable tray due to temperature variations. These hold-downs may not be suitable for high load applications, such as high wind applications. Instead, in such applications a penetrating fastener may be needed to secure the cable tray to the support. For example, a fastener may be driven through a lower flange of a rail of the cable tray and into the support.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure is directed to a hold-down for a cable tray configured to retain the cable tray on a support. In one embodiment, the hold-down is non-penetrating (i.e., the hold-down does not extend through the cable tray or supports) and is configured for high-load applications, such as high wind applications. In this same embodiment, or another embodiment, the hold-down may be configured to retain the cable tray on an I-beam or other beam having a flange. The hold-down may be configured to clamp or otherwise attach to a flange of the I-beam. In this same embodiment, or another embodiment, the hold-down may be configurable between a clamp configuration, in which the hold-down engages or contacts a rail of the cable tray and functions as a clamp, and a guide configuration, in which the hold-down functions as a guide allowing some movement (e.g., expansion) of the cable tray relative to the support.

A hold-down having each of the above-features is indicated generally at reference numeral10throughout the drawings. Referring toFIG.1, a pair of the hold-downs10are used to retain a cable tray, generally indicated at12, on a support, generally indicated at14. In the illustrated embodiment, the support14is an I-beam having an upper flange18. The illustrated cable tray12is of the type comprising a pair of generally parallel side rails, each generally indicated at20, interconnected by a series of parallel, spaced apart cross members22. The cross-sectional shape of the rails20may vary depending on the type of cable tray12. For example, the illustrated rails20are I-beams (e.g., aluminum I-beams), each having a vertical web24and upper and lower horizontal flanges, indicated at25and26, respectively, extending laterally outward from the web, such as on opposite sides of the web. The cable tray12may be adapted to carry various types of conduit. For purposes of illustration, one of the hold-downs10is shown in the clamp configuration, as also shown inFIGS.4-6, and the other hold-down10is shown in the guide configuration, as also shown inFIGS.7-9. It is understood that in use typically each of the hold-downs would be in the same configuration.

Referring toFIGS.2and3, the illustrated hold-down10comprises a support clamp, generally indicated at27, and a hold-down arm, generally indicated at28, secured to the support clamp. The support clamp27includes a main body30, an insert32and one or more upper and lower threaded fasteners34,35. In the illustrated arrangement, the main body30, the insert32and the threaded fasteners34,35are all separate components from one another. However, other configurations also are possible. The insert32is a set screw bar that cooperates with the main body30to support one or more of the threaded fasteners35. In particular, the insert32receives two of the threaded fasteners35and transfers a load from the fasteners to the main body30. The fasteners34,35secure the main body30to the beam or other support14thereby providing a multiple point (e.g., a three point) mechanical connection between the hold-down10and the beam. The upper fastener34also secures the hold-down arm28to the main body30of the support clamp27. The upper and lower fasteners34,35can be aligned with one another in longitudinal and/or lateral directions of the hold-down10, or the fasteners34,35can be offset from one another.

Referring still toFIGS.2and3, the main body30generally comprises a bottom wall40. The main body30also comprises a first side wall42and a second side wall44. The first side wall42extends upward from the bottom wall40and the second side wall44extends upward from the bottom wall40. The first and second side walls42,44can be mirror images of one another. A first top wall46extends inwardly from an upper portion of the first side wall42, and a second top wall48extends inwardly from an upper portion of the second side wall44. The illustrated main body30is hollow and generally rectangular in cross-sectional shape. Preferably, the first top wall46and second top wall48overlap one another along at least a majority portion, e.g., substantially entirety, thereof.

The terms “top,” “bottom,” “side” and the like are merely used to provide a frame of reference for this written description. The structures and component described herein can be mounted in any particular orientation and, therefore, the usage of these terms should not be considered limiting in any manner. Other relative or directional terms may be used herein. These terms are used in the context of the particular orientation(s) shown and should not be considered as limiting the structures to the illustrated orientation in actual use.

The main body30may be formed from a single plate or sheet of material. In other words, the main body30preferably is formed as a monolith or single structure and each of the walls40,42,44,46,48is integrally related. Stated yet another way, each of the adjoining walls (e.g., the top wall40and the first side wall42) is connected at a bend. Other configurations are possible.

The first side wall42has an elongated first slot52extending through an edge54of the first side wall42. Similarly, the second side wall44has an elongated second slot56extending through an edge58of the second side wall44. The slots52and56preferably are aligned in a vertical direction and open in the same direction such that the main body30defines a jaw-like shape with a mouth configured to receive a flange18of the I-beam14, for example. The slots52and56may generally define an L-shape or J-shape when viewed from the side. A first, preferably rectangular, portion60of each of the slots52and56is configured to receive the flange of the beam or a portion of another support member12. A second, preferably rectangular, portion62of each respective slot52and56that is above, is sized and shaped to receive the insert32. The second portion62opens into the first portion60of each slot52and56. A support surface or shoulder64is defined at a juncture between the first portion60and second portion62of each slot52and56so that a portion of the insert32can rest on the shoulder when assembled. The first portion60and second portion62may each be formed by separate slots or openings.

The bottom wall40has a pair of holes68,70sized to accommodate the fasteners35and, preferably, are somewhat, but not substantially, larger than the outer diameter of the shaft portion of the fasteners35. Thus, the holes68,70limit radial movement of the fasteners35. Preferably, the holes68,70are defined by relatively smooth walls. That is, preferably, the holes68,70are not threaded.

The insert32, which can be referred to as a locking bar, is generally elongated and rectangular with a first end positioned in the second portion62of the slot52, and a second end positioned in the second portion62of the slot56. The insert32is in a generally perpendicular relation to the side walls42,44and partially rests on the shoulder64. The insert32has one or more threaded holes to accommodate the threaded fasteners35. Preferably, the insert32has a pair of threaded holes76and78adjacent to the side walls42and44, respectively, and are aligned with the holes68and70, respectively, when the insert32is positioned in the main body30. Thus, the threaded fasteners35preferably pass through a respective one of the holes68,70and threadably engage a respective one of the threaded holes76,78. With the insert32partially resting on the shoulder64, the threaded fasteners35engaging the insert32and the holes68,70of the main body30inhibiting substantial movement of the threaded fasteners35, the insert32preferably is held in place within the second portions62of the slots52,56. That is, the interaction between the threaded fasteners34and the holes68,70restricts a forward end of the insert32from rotating in a downward direction, thereby inhibiting removal of the insert32from the second portions62of the slots52,56. Conveniently, the insert32is held in place even with the threaded fasteners35backed off to ease assembly of the sway brace attachment10to the support, as described further herein.

The first top wall46has a first opening80and the second top wall48has a second opening82that are aligned with one another (FIGS.6and9). In the illustrated arrangement, the first opening80and the second opening82are also aligned in a forward-rearward direction with the openings68,70of the top wall40. Preferably, the openings80,82are centered or substantially centered in a width direction of the main body30. The first opening80and the second opening82are configured to accommodate the threaded fastener34. One of the first opening80and the second opening82may be threaded and the other of the first opening80and the second opening82may be unthreaded. In the illustrated arrangement, the first opening80of the first top wall46(i.e., the relative upper one of the top walls46,48) is threaded and the second opening82of the second top wall48(i.e., the relative lower one of the top walls46,48) is not threaded or is unthreaded. However, in other arrangements, this order could be reversed or both openings80,82could be threaded. The presence of the threaded fastener34within the openings80,82inhibits or prevents significant relative movement between the first top wall46and the second top wall48. In particular, lateral movement of the top walls46,48is inhibited or substantially prevented to inhibit or substantially prevent spreading of the top walls46,48and side walls42,44of the main body30, thereby maintaining the strength of the hold-down10. Thus, the unthreaded opening80or82(if any) is sized relatively closely to the outside diameter of the shaft portion of the fastener34. Although the fastener34may be provided as a means of coupling the top walls46,48to inhibit or at least substantially prevent spreading of the bottom walls46,48, other suitable mechanisms can also be used for this purpose, including fasteners (e.g., rivets, screws) that do not contact the flange, clamps, welding, interference structures and other suitable arrangements for fixing the top walls46,48relative to one another.

In the illustrated arrangement, the upper threaded fastener34(i.e., the threaded fastener passing through the upper walls46,48) includes a nut/washer combination90threadably engaging a threaded shaft portion of the fastener34. The upper threaded fastener34can alternatively comprise a nut without a washer or separate nut and washer.

The hold-down arm28of hold-down10includes a base92having first and second longitudinal ends. The base92can be generally rectangular in shape. Opposite first and second wings94,96extend generally transverse to a longitudinal axis of base92beginning at the respective first and second ends of the base92. Together, interior faces of the base92and wings94,96define a general U-shape and are sized and shapes to nest on top of support clamp27, in particular, to nest on top of top wall46of support clamp27. A fastener opening98extends through base92and is generally aligned with openings80,82of top walls46,48, respectively.

The first wing94extends further downward than the second wing96to define a clamping portion. The clamping portion is configured to engage and clamp the lower flange26of rail20. In the illustrated embodiment, the clamping portion extends downward at an angle of about 90 degrees relative to the base92, although it will be understood that the clamping portion could extend downward at a variety of angles. As illustrated inFIGS.4-6, the hold-down10is shown as mounted in the clamping configuration in which a portion of the base92overlies the lower flange26of the cable tray12and the first wing94is in clamping engagement with the flange26of the cable tray12, thereby holding the rail20of the cable tray12in a fixed position relative to support14.

Referring toFIGS.7-9, the second wing96comprises the guide. In this configuration, the second wing96is not in clamping engagement with the rail20to permit free lengthwise thermal expansion and contraction of the rails relative to the support. The length of the second wing96is preferably sufficient to enable the second wing96to clear (but only slightly), the bead adjacent the outer edge of the lower flange26. In this way, the second wing96is generally shorter in length than the first wing94.

As can be understood and seen byFIGS.4-9, the hold-down arm28can be orientated in either the clamp configuration (FIG.6) or the guide configuration (FIG.9) by merely rotating the hold-down arm28about a transverse axis extending transverse to the length of the hold-down10and through the opposite faces of the hold-down10so that either the clamp (first wing94) engages the rail26or the guide (second wing96) extends over the rail26. There is no need to invert or flip over the hold-down arm28. This makes orientating the hold-down easier and faster for the installer. To further enhance ease of use for the installer, the base92of the hold-down arm98can contain indicia104to indicate which side (i.e., which of the first and second wings94,96) functions as the clamp configuration and which functions as the guide configuration. This indicia104can also be contained on any other part of the hold-down10to indicate to the installer the proper orientation, for example, on first and second wings94,96.

The main body30, the insert, or locking bar,32, and the hold-down arm28can be fabricated from hot-rolled, low-carbon steel to meet the standards set by the Underwriters Laboratories (U.L.), Factory Mutual Engineering (F.M.), or other such quality control groups, though other suitable materials may also be used. Additionally, the main body30and the insert32may have a plain or electro-galvanized finish.

The threaded fasteners34,35may also be referred to herein as set screws. Preferably, each threaded fastener34,35has a head portion and a threaded portion. As described, the threaded fasteners35extends through holes68,70, respectively, and are threaded into the holes76and78of the insert32, thereby capturing the insert32within the slots52,56. The set screws35are long enough to be threaded through the insert32to engage a flange, or other structure, positioned in the slots52,56. Another set screw34preferably extends through the holes80and82of the upper walls46and48, respectively, and hole98of hold-down arm28. This set screw34is long enough to engage the flange, or other structure, positioned in the slots52,56. Each of the set screws34has an end, which preferably is in the form of a relatively sharp cone point for engaging the flange, or other structure. The cone point facilitates the set screws34in creating a deformation in the flange, or other structure, to increase the bite of the set screw34in the flange, or other structure, to inhibit or prevent sliding movement of the set screw34. The cone point does not necessarily need to possess a sharp point. A small flat surface at the end can be permissible. Preferably, any flat surface at the end96is less than about 0.05 inches, less than about 0.04 inches or less than about 0.031 inches. In other arrangements, the end can be a cup point or other type of end structure, if needed or desired.

The screw head may be adapted to break off at a particular torque level or particular torque range, which may be a threshold or predetermined torque level or range. This feature is a convenient method for ensuring that the set screw34has been properly torqued or tightened. A portion of the shaft of the set screw34can include a reduced cross-section portion. The reduced cross-section portion can have a particular minimum diameter (or cross-sectional dimension for non-circular shapes) selected in view of the material properties, heat treatment and/or other relevant factors such that the screw head will break off at a particular torque level, which may be a particular minimum value or a range of values. In one or more embodiments, the screw head may not be configured to break off.

In the illustrated embodiment, the main body30is about 0.25 inches thick. The overall peak dimensions of the main body30are about 3.5 inches high, 2.375 inches wide, and 3 inches long. The lower wall40is preferably about 2.375 inches wide and spaces the inner surfaces of the side walls42and44by about 1.875 inches. The side walls42and44preferably have a peak height of about 3.5 inches. The first portions60of the slots52and56have dimensions of about 1.5 inches by about 0.9 inches (length by height). With such dimensions, the hold-down10is capable of use with flanges between about ⅜ inch and ⅞ inch thickness. The second portions62of the slots52and56have dimensions of about 1.031 inches by about 0.39 inches (length by height). The rearward ends of the first portions60and second portions62are offset from one another such that the shoulder64has a length of about 0.156 inches. The bottom wall40and lower portions of the side walls42,44below the slots52,56have a length (in a forward-rearward direction) of about 2.75 inches. The top walls46,48and upper portions of the side walls42,44above the slots52,56have lengths of about 3 inches. Thus, the lower portions of the edges54,58of the side walls42,44below the slots52,56are offset in a rearward direction from the lower upper of the edges54,58of the side walls42,44above the slots52,56by a distance of about 0.25 inches in a forward-rearward direction. The lengths of the first portions60of the slots52,56are measured from the upper portions of the edges54,58. The upper top wall46has a width of about 1.841 inches and a length of about 3 inches. The lower top wall48has a width of about 1.966 inches and a length of about 3 inches. A vertical gap between the upper top wall46and the lower top wall48is about 0.063 inches. The holes68,70have diameters of about 0.531 inches. The centers of the holes68,70are spaced about 0.891 inches rearward of the forward edge of the bottom wall40, about 1.313 inches from one another and about 0.531 inches from the side edges of the top wall40. The centers of the holes80and82are spaced about 1.141 inches from the front edges of the top walls46,48and substantially centered in the lateral direction of the walls46,48and/or along the center line of the main body30. The threaded hole80has a diameter of about 0.5 inches and the unthreaded hole82has a diameter of about 0.563 inches.

The insert32may be about 0.375 inches thick, about 1 inch wide (forward-rearward or length direction of the assembled sway brace attachment10) and about 2.5 inches in length (lateral or width direction of the hold-down10), which permits it to fit comfortably in the second portions62of the slots52,56and slightly extend outwardly side walls42,44when the insert32is placed in the main body30. The spacing between the threaded holes76and78may be about 1.313 inches, which disposes them in substantial alignment with the holes68and70, respectively. The threaded holes76,78comprise standard ½-inch female threads.

The threaded portion of each set screw34comprises standard ½-inch threads. The shaft portion of the set screw34, including the threaded portion, end and reduced cross-section portion can be about 2.5 inches in length, so that the cone point can extend into the area defined between the slots52and56. The reduced cross-sectional portion can have a length of about 0.188 inches. The set screws34can be fabricated from a hardened carbon steel, though other suitable materials may be used. Of course, those skilled in the art will recognize that these and other dimensions presented herein are illustrative of one preferred embodiment, and that the present disclosure may be alternatively dimensioned with efficacy, as required or desired.

The hold-down10is capable of withstanding a large force in multiple directions. For example, the hold-down10is capable of withstanding a large force applied transverse to the longitudinal axis of the cable tray12away from the support and transverse to the axis of support14away from the support (“tray pull-off” load). The hold-down10is also capable of withstanding a large force applied transverse to the longitudinal axis of the cable tray12and along the longitudinal axis of support14(“across the tray” load). Either or each of the tray pull-off load and the across the tray load may be over 2,000 lbf. (8,896 N), over 2,250 lbf. (10,008 N), over 2,500 lbf. (11,121 N), over 2,750 lbf. (12,233 N), over 3,000 lbf. (13,345 N), over 3,250 lbf. (14,457 N), or over 3,500 lbf. (15,569 N), for example, from 2,000 lbf. to 5,500 lbf. (8,896 N to 24,688 N), from 2,250 lbf. to 5,500 lbf. (10,008 N to 24,688 N), from 2,500 lbf. to 5,500 lbf. (11,121 N to 24,688 N), from 2,750 lbf. to 5,500 lbf. (12,233 N to 24,688 N), from 3,000 lbf. to 5,500 lbf. (13,345 N to 24,688 N), from 3,250 lbf. to 5,500 lbf. (14,457 N to 24,688 N), or from 3,500 lbf. to 5,500 lbf. (15,569 N to 24,688 N) in either or both the clamp and guide configurations.

Also provided herein is a method of securing a cable tray to a support, such that the cable tray is able to withstand a large force. The method generally comprises positioning the hold-down10in the correct configuration (i.e., clamp configuration or guide configuration) relative to the lower flange26of the rail20of cable tray12and sliding slots52and56of the support clamp27over the flange18of support14, as shown inFIG.1. The lower set screws35(i.e., the set screws that engage the insert32) are inserted through respective holes68and70in the main body30and threaded into holes76and78in the insert32until the cone points of set screws35make contact with the flange. The set screws35can be tightened until their heads break off, whereby the set screws35securely contact the flange. Before or after inserting set screws35, the hold-down arm28is aligned with support clamp28and the upper set screw34is inserted through fastener openings80,82, and98. The upper set screw34(e.g., the set screw that engages the main body30) is tightened until its head breaks off. This results in the hold-down10being securely fastened to the flange18of the support14. As described, the provision of upper and lower set screws34,35increases the bite of the hold-down10on the flange18of support14to increase resistance to overturning (rotation) of the hold-down10. This method allows the cable tray to securely withstand large forces as described herein.

Referring toFIGS.10-16, another embodiment of a hold-down capable of withstanding a large force in multiple directions, as described above, is generally indicated at reference numeral110. The hold-down generally includes a support clamp, generally indicated at120, and a hold-down arm, generally indicated at125, coupled to the support clamp. The support clamp includes a clamp body121, a set screw bar122coupled to the body, and at least one set screw124(e.g., two set screws or more than two set screws) coupled to the set screw bar. The illustrated body120is generally C- or channel-shaped, although it may be of other shapes. The illustrated body121includes a back wall128and opposing left and right side walls, generally indicated at130a,130b, respectively, extending forward from the back wall. Together, the back wall128and the side walls130a,130bdefine an open channel129having open upper and lower ends and an open front side. In the illustrated embodiment, the body120is integrally formed as a one-piece, monolithic component. For example, the body120may be fabricated from sheet metal, such as steel or other metal, as would be readily apparent by one of ordinary skill in the art.

The left and right side walls130a,130bdefine slots138a,138b, respectively, extending through a front of the respective side walls toward the back wall128. The slots138a,138bare generally aligned with and oppose one another and are sized and shaped to receive a flange (or other portion) of the structural support (e.g., a flange of a beam, such as an I-beam). Accordingly, the left and right side walls130a,130bmay be generally C-shaped. The left and right side walls130a,130binclude upper arms140a,140band lower arms142a,142bon opposite sides of the respective slots138a,138b. As indicated inFIG.12, upper surfaces144a,144bof the left and right side walls130a,130b(e.g., upper surface of the upper arms140a,140b) are chamfered or beveled toward the front side of the sway brace110. The hold-down arm125sits on these upper surfaces144a,144b, as explained in more detail below, such that the hold-down arm is tilted or sloped downward toward the front side of the attachment110.

As shown inFIG.12, the side walls130a,130b(e.g., the upper arms140a,140b) define aligned and opposing openings148a,148b, respectively, disposed above the slots138a,138b. The openings148a,148bare sized and shaped to receive and capture the set screw bar122therein. In the illustrated embodiment, the openings148a,148bare generally rectangular, similar to the set screw bar122, having a slightly larger area than the cross section of the bar so that the set screw bar is slidably receivable therein and captured. The openings148a,148bare configured such that when the bar122is received therein, the bar is tilted or sloped downward toward the front side of the attachment10. In this way, as shown best inFIG.15, a plane P2of the bar122is angled relative to the axes A3of the slots138a,138b. For example, the bar122may be angled between about 10 degrees and about 60 degrees, or about 15 degrees to about 30 degrees, or in one example about 15 degrees. As coupled to the side walls130a,130b, opposite end portions of the set screw bar122extend outward from the corresponding side walls130a,130b(e.g., upper arms of the corresponding side walls). The opposite ends of the bar122define openings150configured to receive set screws152. The illustrated openings150are threaded to threadably receive the set screws152. The axes A4of the openings150(and axes of the fasteners, indicated by the same reference numeral) extend at an acute angle (i.e., less than 90 degrees) from the longitudinal axis of the bar122and the axis A3defined by the slots138a,138bto enhance the strength of the connection to the beam or other structural support. In this way, the set screws124engage the flange of the structural support outside the body120and the channel129and at an angle less than 90 degrees (i.e., an acute angle) when threaded through the openings150. For example, the set screws124may engage the flange at an angle from about 85 degrees to about 60 degrees, or from about 80 degrees to about 75 degrees. The set screws124may have torque off head that are sheared off the screws after a predetermined or threshold amount of torque is applied to the head.

Like the first embodiment of the hold-down arm28, the present embodiment of the hold-down arm128includes a base192having first and second longitudinal ends. The base192can be generally rectangular in shape. Opposite first and second wings194,196extend generally transverse to a longitudinal axis of base192at the respective first and second ends of the base192. Together, interior faces of the base192and wings194,196define a general U-shape and are sized and shapes to nest on top of the body120, in particular, to sit or rest on the upper surfaces144a,144b. A fastener opening198(e.g., non-threaded opening) extends through the base192and is generally aligned with a threaded central opening180in the set screw bar122so that the threaded fastener126extends through the fastener opening198and threads into the opening180in the set screw bar to couple the hold-down arm128to the set screw bar122and position the hold-down arm relative to the lower flange26. In addition, the set screws124extend through openings182(e.g., non-threaded openings) in the base192and thread into the threaded openings150in the set screw bar122to secure the support clamp120to the support18. The axes A4of the openings150(and axes of the fasteners, indicated by the same reference numeral) extend at an acute angle (i.e., less than 90 degrees) from the longitudinal axis of the base192of the hold-down arm122(and the bar plane P2) to enhance the strength of the connection to the beam or other structural support.

As secured to the body120, the hold-down base192is tilted or sloped downward toward the front side of the hold-down110. In this way, a plane P3of the base192is angled relative to the axes A3of the slots138a,138b. For example, the base192may be angled between about 10 degrees and about 60 degrees, or about 15 degrees to about 30 degrees, or in one example about 15 degrees. The first and second wings194,196extend at an acute angle (i.e., less than 90 degrees), as indicated by axis A4, from the longitudinal axis (and plane P3) of the base192of the hold-down arm122. Ends of the wings194,196are also tapered to a point, although the ends of the wings may be blunt, such that portions of the ends are parallel to the axis A3.

The first wing194extends further downward than the second wing196to define a clamping portion. The clamping portion is configured to engage and clamp the lower flange26of rail20. In the illustrated embodiment, the clamping portion extends downward at an acute angle (i.e., less than 90 degrees) from the longitudinal axis (and plane P3) of the base192of the hold-down arm122(and the bar plane P2) to enhance the strength of the connection to the beam or other structural support, although it will be understood that the clamping portion could extend downward at a variety of angles. As illustrated inFIG.13, the hold-down110is shown as mounted in the clamping configuration in which a portion of the base192overlies the lower flange26of the cable tray12and the first wing194is in clamping engagement with the flange26of the cable tray12, thereby holding the rail20of the cable tray12in a fixed position relative to support14.

Referring toFIG.14, the second wing196comprises the guide. In this configuration, the second wing196is not in clamping engagement with the rail120to permit free lengthwise thermal expansion and contraction of the rails relative to the support. The length of the second wing196is preferably sufficient to enable the second wing196to clear (but only slightly), the bead adjacent the outer edge of the lower flange126. In this way, the second wing196is generally shorter in length than the first wing194.

As can be understood and seen byFIGS.13and14, the hold-down arm128can be orientated in either the clamp configuration (FIG.13) or the guide configuration (FIG.14) by merely rotating the hold-down arm128about a transverse axis extending transverse to the length of the hold-down110and through the opposite faces of the hold-down110so that either the clamp (first wing194) engages the rail126or the guide (second wing196) extends over the rail126. There is no need to invert or flip over the hold-down arm128. This makes orientating the hold-down easier and faster for the installer. To further enhance ease of use for the installer, the base192of the hold-down arm198can contain indicia204to indicate which side (i.e., which of the first and second wings194,196) functions as the clamp configuration and which functions as the guide configuration. This indicia104can also be contained on any other part of the hold-down110to indicate to the installer the proper orientation, for example, on first and second wings194,196.

The hold-down110is capable of withstanding a large force in multiple directions. For example, the hold-down110is capable of withstanding a large force applied transverse to the longitudinal axis of the cable tray12away from the support and transverse to the axis of support14away from the support (“tray pull-off” load). The hold-down110is also capable of withstanding a large force applied transverse to the longitudinal axis of the cable tray12and along the longitudinal axis of support14(“across the tray” load). Either or each of the tray pull-off load and the across the tray load may be over 2,000 lbf. (8,896 N), over 2,250 lbf. (10,008 N), over 2,500 lbf. (11,121 N), over 2,750 lbf. (12,233 N), over 3,000 lbf. (13,345 N), over 3,250 lbf. (14,457 N), or over 3,500 lbf. (15,569 N), for example, from 2,000 lbf. to 5,500 lbf. (8,896 N to 24,688 N), from 2,250 lbf. to 5,500 lbf. (10,008 N to 24,688 N), from 2,500 lbf. to 5,500 lbf. (11,121 N to 24,688 N), from 2,750 lbf. to 5,500 lbf. (12,233 N to 24,688 N), from 3,000 lbf. to 5,500 lbf. (13,345 N to 24,688 N), from 3,250 lbf. to 5,500 lbf. (14,457 N to 24,688 N), or from 3,500 lbf. to 5,500 lbf. (15,569 N to 24,688 N) in either or both the clamp and guide configurations.

Also provided herein is a method of securing a cable tray to a support, such that the cable tray is able to withstand a large force. The method generally comprises positioning the hold-down110in the correct configuration (i.e., clamp configuration or guide configuration) relative to the lower flange26of the rail20of cable tray12and sliding slots130a,130bof the support clamp120over the flange18of support14. The fasteners124are tightened to secure the support clamp120to the flange18. The fastener126is tightened to position the corresponding wing194,196of the hold-down arm relative to the lower flange26of the rail20.

In view of the above, it will be seen that several features of the disclosure are achieved and other advantageous results obtained.

Having described the disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. For example, where specific dimensions are given, it will be understood that they are exemplary only and other dimensions are possible.