Purlin hanger

Abstract: A purlin hanger (31) is used for suspending a wide variety of items from many different types of purlins which may be horizontal or sloping. The hanger is primarily a rigid high strength generally C-shape frame or body (31) which includes an angled upper end (32) and an offset lower end (33). The angled upper end bears against the interior corner at the web and lower flange of the purlin (20). The lower end is slightly offset from the exterior of such corner and has a tapped hole to receive a threaded hanging rod to which a wide variety of clip or clamps may be attached. The body of the C-shape frame extends with considerable clearance around the purlin lower flange and any treatment of the edge of such flange such as a fold or further flange. An adjustable shim (50) is positioned between the lower end of the body and the exterior of the web and lower flange corner of the purlin. The hanger engages the purlin at the interior corner and avoids a load with any significant moment arm on any part of the flange of the purlin.

Description: This invention relates generally as indicated to a purlin hanger, and more particularly to a universal purlin hanger which can be affixed to a wide variety of purlins without placing any significant load on the purlin lower flange. Purlins are struts or beams usually employed in roof decking for supporting the decking or common rafters. They are usually rolled in a variety of transverse or sectional shapes which can be described generally as C, Z, or S shape. A common feature is usually, however, a generally vertical web and usually top and bottom flanges. The flange edges may be subject to further treatment such a further flange or double flange with a flat or bulb fold. The purlins may extend horizontally or at an angle and vary significantly in dimension or gauge. For example, purlins may be from 100 to 300mm high and have flange widths or extents of from 50 to 80mm, with treated edges or lips which may be 10-20mm high. The gauge or thickness may vary from about 1.5 to 3mm. It is often desirable to suspend a wide variety of items from purlins, such as piping, wiring conduit, ducts, fixtures or suspending ceilings, with up to about 100 kg static working load. Such items are most often suspended with threaded rod, and with other clips and clamps. Items are hung from purlins in a number of different ways. One common way is to drill holes in purlins to accommodate fasteners to attach certain types of hangers. The process is labor intensive and requires additional tools (drills, wrenches, screw drivers, e.g.). Such attachments seldom permit adjustment, at least without addition holes, and sometimes drilling is forbidden, especially in lower flanges, which weakens the purlin section, not to mention any coating of the purlin. Some clips or purlins clamps are available which engage either the lower or both flanges of the purlin. These clips or clamps, while effective, have reduced capacity, particularly with thin gauge purlins. Purlin flanges may be relatively fragile and are meant primarily to add strength and stiffness to purlin sections as a whole. Accordingly, any deformation of the flanges may put the stability of the whole purlin at risk as well as any attachments. It is desirable that the clip load not be at the very edge of the flange since the extent of the flange acts as a moment arm contributing to distortion. Some clips try to distribute the load to both flanges. While this reduces the risk of deformation, the upper flange is not always accessible even if various heights, dimensions and configurations of flange pans can be met or accommodated. The industry has thus developed a number of hangers which are for specific types of purlins, rather than a universal hanger for many designs of purlins. Examples for known hangers or fasteners which are attached to or secured directly on structural flanges are disclosed by EP-A-0 319 389 and GB-A-516 104, respectively. Any force or load exerts a force or moment on the particular flange in both disclosures. EP-A-0 319 389 discloses a hammer-on clip that is to be driven on the flange of a steel beam having an I or H profile. GB-A-516 104 discloses a clip for a purlin which clip closely embraces substantially the entire bottom flange and any load on the clip is a load on the flange or provides a moment on the flange. From a hook to locking tongues almost the entire bottom flange is closely embraced by the clip, except for the inside comer. Although the device supports panels it is apparent that any load is a load on the flange. The object of the invention is to have a purlin hanger which does not require holes in the purlin; which does not place a load on the purlin flange, and particularly a load at the edge of the flange; and also which fits a wide variety of types and sizes of purlins. The purlin hanger of the present invention is used for suspending a wide variety of items such as piping, wiring conduit, ducts, lighting, ceilings and the like, from many different types of purlins which may be horizontal or sloping. The hanger is primarily a rigid high strength generally C-shape frame or body which includes an angled upper end and an offset lower end. The angled upper end bears against the interior corner at the web and the lower flange of the purlin. The lower end is slightly offset from the exterior of such corner and includes a tapped hole to receive a threaded hanging rod to which a wide variety of clips or clamps may be attached. The body of the C-shape frame extends with considerable clearance around the purlin lower flange and any treatment of the edge of such flange such as a fold or further flange. An adjustable shim may be positioned between the lower end of the body and the exterior of the web and lower flange corner of the purlin. The shim may be in the form of a plastic cap which is slipped on the lower end of the frame and which includes a vertical hole accommodating the threaded rod or other hanger extending through the tapped hole. The cap includes a rounded asymmetrical shoulder adapted to bear against the exterior corner at the web and the lower flange of the purlin when the threaded rod is in place. Adjustment is obtained simply by turning the cap end-for-end. Such adjustment would be occasioned by a change in thickness or gauge of the purlin, or perhaps by an alteration of the external radius or configuration at such corner. The C-shape body or frame is preferably made as a cast or forged metal alloy, which may include a strengthening spine around the exterior. Alternatively, the frame may be made by transversely cutting an extrusion. It may also be made from steel sheet with pressed ribs for reinforcement. The hanger engages the purlin at the interior corner and avoids a load with any significant moment arm on any part of the flange of the purlin. In the drawings Figure 1 is a transverse view of a purlin with a hanger in accordance with the present invention secured thereto; Figure 2 is an enlarged sectional view of the engagement of the hanger and purlin; Figure 3 is an enlarged perspective view of the adjustable shim which may be used with the hanger; Figure 4 is an exploded view of the threaded rod and shim; Figure 5 is an enlarged view similar to Figure 1 but illustrating clearances or angular variations of the purlin or hanger which may be accommodated by the hanger; Figure 6 is a top plan view of the hanger body or frame; Figure 7 is a view similar to Figure 1 but showing the use of an intermediate rod hanger which may extend at an angle; Figures 8 and 9 are views similar to Figure 1 showing the installation and use of a simpler form hanger for use with relatively simple purlins and without a shim; and Figures 10 and 11 are views like Figures 8 and 9 but with the hanger modified for a different form purlin and having a contact area beneath the purlin flange. Referring initially to Figure 1, there is illustrated a purlin shown generally at 20 which comprises a vertical web 21, a top flange 22 and a bottom flange 23. Both flanges terminate in rebent short flange section edges as seen at 24 and 25, respectively. What is illustrated is generally know as a Z-purlin. Some Z-purlins more closely resemble the letter Z with the web extending at a slight angle and the flanges directly above one another. If the flanges extend in the same direction, it is known as a C-purlin. Purlins come in a wide variety of shapes and such purlins may generally be described as C, Z, or S shape. For generally all such purlins, a common feature is the vertical web and the top and bottom flanges. Typically, a roof or rafters are supported on the top flange and the bottom flange or edge of the purlin is exposed. As indicated, purlins may extend horizontally or at an angle and may vary significantly in dimension or gauge. The hanger of the present invention is illustrated generally at 30 and comprises a generally C-shape body or frame 31 which includes an upper end 32 and a lower end 33 which are fairly closely spaced to each other. The gap should be enough to accommodate any edge treatment of the flange. The ends of the C-shape body are seen in Figures 1, 2, 5, 6 and 7. As seen more clearly in Figure 6, the lower end 33 projects beyond the upper end 32 and terminates in what might be termed a circular collar 34 which includes a tapped hole 35 adapted to accommodate threaded rod 36. The lower leg of the frame or body extends generally horizontally as indicated at 38 but then extends downwardly as shown at 39 before extending upwardly to form the back of the C as indicated at 40 in Figure 5. The top leg of the C-body extends downwardly at an angle as indicated at 42 and then terminates at an even sharper angle as seen at 43. The back of the C at 40 is slightly outwardly curved so that the body or frame has a relatively large interior 45 which completely clears the lower flange of the purlin and any edge treatment thereof such as shown at 25 in Figure 1. As can be seen more clearly in Figures 1, 2, 5 and 7, the upper end of the C of the body indicated at 32 is designed to engage the interior 47 of the corner between the web 21 and lower flange 23 of the purlin. For this purpose, the very tip of the C-shape body is rounded or radiused such that it will generally match the interior radius of the purlin. The lower end of the body extends beyond the web as seen in Figure 2 so that the threaded rod 36 extends upwardly adjacent the web but on the opposite side as the upper leg of the body. In order to provide stability and tightness to the hanger, the hanger includes an adjustable shim shown generally at 50 in Figures 1-5 and 7. The adjustable shim has a generally circular main body 52 with two arcuate diametrically spaced and opposed depending skirt portions 53 and 54. A tapered normally unthreaded hole 55 extends upwardly through the circular body. The top of the circular body is provided with two concave somewhat conical sections or shoulders 57 and 58 which are separated by a diametrical slot 59. It is noted that the slot 59 extends perpendicular to the gap between the two depending skirt portions. The hole 55 is such that when the threaded rod 36 projects upwardly through and just above the hole or the top of the shim as seen in Figures 1 and 2, the two concave upper portions of the shim are pushed apart and the radius formed by the concavity will snugly engage the exterior of the corner between the web 21 and flange 23 which is shown at 60 in Figure 2. The shim is adjustable in that the concave upper sides of the shim are asymmetrical about the axis. For example, the side on the right hand side of Figure 4 may be somewhat thinner than the side on the left hand side and the right hand side is thus used for relatively thick purlins such as 2 to 3mm. The thicker side on the left is used for relatively thinner purlins such as 1.5 to 2mm. The adjustment is obtained simply by turning the cap or shim end-for-end when it is inserted on the lower end of the C-body with the tapped hole end or collar 34 snapping between the skirts 53 and 54. When the threaded rod is in place, the upper end of the shim is distorted to press against the exterior of the corner of the purlin opposite the upper end of the C-body engaging the interior of the corner. Referring now to Figure 5, it will be seen that the purlin web 62 illustrated is not straight or vertical but includes an angled portion 63. Also the purlin flange 64 includes a ridge 65. The configuration of the upper portion of the C-body is such that the upper end of the body fits nonetheless in the interior corner and the opening 45 is sufficient to accommodate any edge treatment 66 of the flange at a number of swivel or pivot angles. For example, the purlin may be at the phantom line positions 67 or 68 which are approximately 15° on each side of the center position. In this manner, the angle of the rod may vary considerably with respect to the purlin orientation. As seen in Figures 1, 5, 6 and 7, the C-shape body may be in radial section in the form of a variable stem T with the head 70 being an axial or transverse flange while the stem 71 acts as a spine. The radial extent of the spine varies, being least at the ends. The body of the C may be cast from a suitable alloy or forged. In addition to the above, it will be appreciated that the C-shape bodies in a more plain form may be formed by a metallic extrusion which is then simply transversely sliced to form the C-shape body before drilling and tapping the lower projecting end. A C-shape body such as shown may be made in this fashion. The body may also be made from steel sheet with pressed ribs for reinforcement. Also, two bodies side-by-side and connected to each other may be used. Referring now to Figure 7, it will be seen that instead of the utilization of a threaded rod 36, a relatively short bolt 78 of the same size may be employed to secure to the underside of the hanger an accessory hanger 79. The hanger 79 may swivel at any angle around the axis of the bolt 78 and extend at substantially any acute angle to the portion of the accessory captured by the bolt. The threaded rod 36 is then secured to the accessory as indicated at 80. While the hanger itself may enable angular variations up to from about 15 to 20°, as indicated in Figure 5, for larger angular variations, the accessory of Figure 7 may be employed. In Figures 8 and 9, there is illustrated a somewhat more simplified C-shape body and hanger system. The body 82 includes an upper arm 83 ending in a downwardly extending end or tip 84. The back 85 of the body is generally straight and the lower arm of the body 86 is generally parallel to the upper arm 83 and projects beyond the tip 84 as indicated at 87. The lower arm at the end is provided with a tapped hole 88 to accommodate threaded rod 36. Like the embodiment of Figure 1, there is a gap or space 90 between the tip of the upper end of the body and the lower end or leg. This gap is designed to accommodate any edge treatment of the lower flange 23 such as a bulb fold or rolled edge. As seen in Figure 8, the body may be installed by turning it up to permit the flange 25 to enter the gap 90 and then simply turning the body in the direction of the arrow 92 to achieve the position seen in Figure 9. When the threaded rod is inserted as seen in Figure 9, it will extend upwardly a somewhat greater extent and the side of the rod will abut the web of the purlin from the exterior corner to approximately the same height as the body on the opposite side of the web. In Figures 10 and 11, there is illustrated a hanger with a somewhat modified C-shape body 94. The top leg 95 has an angled nose 36 to duck under or clear the angled web 97 of purlin 98. The lower horizontal leg 101 includes the jutting tapped hole 102 for threaded rod 36 and has an interior enlarged or thickened portion 106 adapted to contact the underside of the lower flange 108 of the purlin 98. The contact area of the enlargement assures a form lock when the hanger is assembled simply by installing as in Figure 10 by rotating in the direction of the arrows 110 and 111, and then inserting the threaded rod 36 to an elevation adjacent the exterior of the web at the corner, as illustrated. As in the simplified forms of Figures 8-11, the form lock is assured even though the rod cannot pivot. It can now be seen that there is provided a hanger which engages the purlin at the bottom end of the web and which clears the lower flange of the purlin and avoids putting any force on the lower flange through any significant moment arm which might cause distortion of that flange. It will also be seen that the hanger of the present invention fits a wide variety of purlins and may be quickly secured to the purlin, whether that purlin be horizontal or at an angle. The adjustable shim accommodates a variety of purlins which vary in thickness.

Claims: Purlin hanger, comprising in combination a purlin (20) including a web (21) and a lower projecting flange (23) forming a corner with an interior (47) and an exterior (60), and a hanger (30) comprising an almost closed C-shape body (31) having an upper end (32) and a lower end (33) relatively closely spaced, and means (35) to hang something from the lower end of the C-shape body (31), characterised by the upper end (32) of the C-shape body (31) of the hanger (30) being shaped to nest in the interior (47) of the corner between the web (21) and the projecting lower flange (23) of the purlin (20), the lower end (33) of the C-shape body (31) being positioned adjacent the exterior (60) of the comer between the web (21) and the projecting lower flange (23) of the purlin (20), the C-shape body (31) clearing the lower projecting flange (23) of the hanger (30) so that no load with any significant moment arm is placed on the lower projecting flange (23). Purlin hanger as set forth in claim 1, wherein the lower end (33) of the C-shape body (31) includes a tapped hole (35) to receive a threaded rod (36). Purlin hanger as set forth in one of claims 1 or 2, wherein form locking means (50) operative to engage the purlin (20) to maintain the C-shape body (31) of the hanger (30) in its proper position are provided. Purlin hanger as set forth in claim 3, wherein the form locking means (50) engages the exterior (60) of the comer between the web (21) and the lower projecting flange (23) of the purlin (20). Purlin hanger as set forth in one of claims 1 to 4, wherein a shim (50) is provided on the lower end (33) of the C-shape body (31) adapted to bear against the exterior (60) of the comer between the web (21) and the lower projecting flange (23) of the purlin (20). Purlin hanger as set forth in one of claims 1 to 5, wherein a shim (50) in form of a plastic cap is wedged on the lower end (33) of the C-shape body (31) between said body (31) and the exterior (60) of the corner between the web (21) and the lower projecting flange (23) of the purlin (20). Purlin hanger as set forth in one of claims 5 to 6, wherein the shim (50) on the lower end (33) of the C-shape body (31) is adjustable by rotating the shim about a generally vertical axis. Purlin hanger as set forth in one of claims 5 to 6, wherein the shim (50) on the lower end (33) of the C-shape body (31) is adjustable by turning it end-for-end. Purlin hanger as set forth in one of claims 1 to 8, wherein the lower end (33) of the C-shape body (31) is offset from the upper end (32) whereby a vertical line through the lower end (33) of the C-shape body (31) clears the exterior (60) of the comer between the web (21) and the lower projecting flange (23) of the purlin (20). Purlin hanger as set forth in one of claims 1 to 9, wherein the upper end (32) of the C-shape body (31) of the hanger (30) is radiused to fit the interior (47) of the comer between the web (21) and the lower projecting flange (23) of the purlin (20). Purlin hanger as set forth in one of claims 1 to 10, wherein the interior of the C-shape body (31) of the hanger (30) is shaped to clear the lower projecting flange (23) of the purlin (20) and any bent or folded treatment (25) of the edge of such flange. Purlin hanger as set forth in one of claims 1 to 11, wherein the interior of the C-shape body (31) of the hanger (30) is large enough to enable the C-shape body to pivot about its point of engagement with the purlin (20). Purlin hanger as set forth in one of claims 1 to 15, wherein the upper end (33) of the C-shape body (31) of the hanger (30) extends downwardly and outwardly at an acute angle (43) to the lower end (32) of the C-shape body (31) of the hanger (30). Purlin hanger as set forth in one of claims 1 to 13, wherein the lower end (32) of the C-shape body (31) of the hanger (30) is formed by a leg (101) having an enlargement (106) adapted to engage beneath the lower projecting flange (108) of the purlin (98). Purlin hanger as set forth in one of claims 1 to 14, wherein the C-shape body (31) of the hanger (30) is a metal casting or forging. Purlin hanger as set forth in one of claims 1 to 14, wherein the C-shape body (31) of the hanger (30) is formed of sheet steel. Purlin hanger as set forth in one of claims 1 to 14, wherein the C-shape body (31) of the hanger (30) is a transverse slice of a metallic extrusion.

Inventors: VAN LEEUWEN MARTIN, VAN LEEUWEN, MARTIN
Applicants: ERICO INT CORP, ERICO INTERNATIONAL CORPORATION
Application year: 1996
Main classification: E04B9
IPC codes: E04B9