This invention relates generally as indicated to a fabricated heavy duty structural clamp, and more particularly to a low cost yet light weight heavy duty clamp using primarily threaded rod for fixing and hanging a variety of items such as pipe, lighting and heating fixtures, duct work, cables or cable trays from a variety of structural members such as beams, struts, Z-purlin, T-bars, or other structural shapes.
Heavy duty clamps such as beam clamps are often used as hangers and have a notch or jaw opening receiving an edge of a structure flange such as a beam. The upper part of the jaw is provided with a clamping bolt or set screw directed to the lower or bottom jaw. A flange fits in the jaw and as the clamping bolt or screw is tightened against the top of the flange the clamp is secured to the flange of the structure. An object supported by the clamp is often supported by a threaded rod which may extend through a nut or thread form in the body of the clamp clear of the edge of the flange. However some clamps secure the rod to a thread form in the bottom of the jaw in alignment with the clamping bolt. Other items are hung or supported with intermediate fixtures to support wiring, conduit, swivel connections or even struts.
Heavy duty clamps used in the construction industry have long been made from castings, usually cast iron. These castings were typically made by smaller job shop foundries. Over the last several decades these foundries have disappeared from the American industrial scene, primarily because of costly environmental restrictions. Today most castings of the type in question are made overseas and primarily in Asia. The long transportation costs makes even the raw casting expensive even before it is subjected to further expensive machining such as drilling, taping, cutting or finishing. However, even in Asia environmental considerations are beginning to impact such industries making job shop castings even more difficult or expensive to obtain. Complicating the matter further is that heavy duty clamps may vary widely in size dimensions, such as height and width, and other dimensions which makes the procurement of castings for such heavy duty clamps much more difficult. Also, the material properties of castings can vary widely from run to run even from the same source, leading to unpredictable clamp performance.
Heavy duty clamps are typically commodity items that have a cast iron body with a variety of threaded or plain primary openings to accept threaded rod, and a set screw/jam nut combination for affixing the clamp to a structural member, and may include secondary openings to accommodate intermediate fasteners such as bridle rings or conduit clamps.
As a result of this trend a number of smaller lighter weight clamps are being fabricated from relatively thin sheet metal. Examples of these smaller clamps are sold under the well known CADDY® trademark by ERICO International Corporation of Solon, Ohio, U.S.A. under the part numbers BC. However larger heavy duty beam and other type clamps are still made from castings.
There is accordingly a need for a sturdy and yet versatile low cost fabricated heavy duty yet light weight clamp which will provide the same advantages as cast iron for example, but at a lower cost and more reliable uniform quality.
In one preferred embodiment of a heavy duty structure hanger clamp in accordance with the invention, a spacer block has at least one hole with side plates secured to the spacer block, and each having a notch having one side extending beneath the hole. Threads in the hole receive a clamp screw to clamp a structure against the one side of the notch to secure the clamp to the structure. An opening between the side plates offset from the hole and the notches enables something to be supported from the clamp offset and clear of the structure. The side plates may be formed from a continuous U-shape plate and a threaded rod extends through the opening and a clasp or clip is positioned on the rod interfitting with the plates to capture the clasp and rod. The clasp may be a common nut or push nut, or a slip-on nut of the type seen in Applicant's Assignee's U.S. Pat. No. 6,050,766. A slot may be provided in the plates to capture the clasp or nut.
In another preferred form of the invention, the heavy duty fabricated hanger clamp of the invention comprises a spacer block having at least one primary hole. Side plates are secured to the spacer block and each side plate has a notch having one side, usually the bottom, extending beneath the primary hole. Threads are formed in the primary hole to accommodate a clamp screw which, when tightened, will clamp a structure flange and the like accommodated in the notch against the far side of the notch.
The same block or another block may include another primary hole clear of the interior of the notch which will accommodate a threaded rod projecting past the edge of the structure flange or any other structure clamped in the notch. The other primary hole may be threaded or un-threaded. If threaded the threads may mesh with the rod if sized matched. If the threads are larger or the hole is un-threaded the rod will project through and be held in suspended vertical position by a variety of devices, which may range from a nut threaded on the rod, with or without a lock nut, to a jam nut, a spring steel bobby pin clip, or a two part slip-on nut such as seen in the noted prior U.S. Pat. No. 6,050,766.
Some clamps may be provided with two primary holes vertically aligned accommodating threaded rod, one above the other. One may be threaded and one not. If two vertically spaced holes are provided clear of the structure flange, an additional spacer block is provided for the additional hole although both offset holes may be provided in a single, vertically extended block.
For some heavy duty hangers it is desired to position the hanging rod in vertical alignment with the clamp screw, and a spacer block with a threaded hole may be provided between the side plates bridging the bottom edge of the notch with a threaded primary hole aligned with the primary hole accommodating the clamp screw. The top of the threaded rod is then threaded into the threaded primary hole beneath the notch and tightened against the structure or flange in the notch further clamping the hanger in place.
By primary hole is meant a hole accommodating either a threaded rod or the clamping screw. It will be appreciated that the various spacing blocks may be provided with other holes, usually smaller, threaded and un-threaded, which may accommodate a variety of intermediate fasteners such as bridle rings, conduit clamps, or drop wire attachments.
For strength each side plate may be two or more side plates. The various spacer blocks positioned between the side plates may be machined and cut from longer standard stock with the holes formed before or after assembly. Also the blocks may be formed or built up from vertical laminations of plates with the width of the heavy duty clamp determined by the number of laminations. A block thus constructed may be provided between the far side or bottom of the notch or clamping jaw to provide a larger and more effective clamping area opposite the clamp screw. A block of this type may or may not be provided with the primary threaded hole for the threaded rod as discussed above.
If formed of the laminations indicated the assembly with the side plates may be accomplished by through-pins or rivets which may be assembled in a pressing or stamping operation. Even with machined blocks it is preferred to provide those blocks with projections or wings which will project through notches or holes in the side plates with the projecting ends being coined, pressed or swaged to complete the assembly. Although not necessarily preferred, the laminated plates and side plates may be secured together by welding or bolting or other fasteners.
Accordingly, with relatively simple stamping or pressing manufacturing and assembly steps a heavy duty yet light weight structure hanger clamp can be formed providing the performance of cast hangers but none of the uncertainties such as cost, availability or performance from lot to lot.
To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
Referring initially to the embodiment illustrated in
Secured between the projecting legs 21 and 22 is a spacer block 24 provided with a center tapped hole 25.
The edges of the side plates away from the bight portion 23 are each provided with a notch or cutout indicated at 26 and 27, respectively. The notches are horizontally aligned and form jaw openings with the bottom edge of the openings projecting beneath the tapped hole 25. Positioned between the bottom projecting ends 28 and 29 of the side plate is a bottom block 32.
The top block 24 is held in place by two pin rivets shown at 34 and 35. Similarly, the bottom block 32 is held in place by transverse pin rivets 36 and 37. The pin rivets and blocks may be assembled and coined, or swaged, in a relatively simple stamping operation, and when assembled form a unitary structure for the fabricated heavy duty structure clamp illustrated.
It is noted that the bottom of the jaw openings are generally parallel to the bottom of the structure clamp and are designed to accommodate the bottom of a projecting flange which will fit within the jaw. A clamp screw, not shown, threaded in the opening 25 is then tightened on top of the projecting flange to clamp the illustrated structure firmly to the flange edge.
Beyond the interior of the jaw opening, and thus the lateral edge of the flange, the clamp structure has a vertically extending through-opening illustrated generally at 40. The through-opening is generally centered with respect to the semi-circular bight portion 23. This through-opening accommodates a threaded rod shown generally at 42 in
In any event the fabricated heavy duty structural clamp seen in
Referring now to the embodiment of
Referring now to
Referring now to the embodiment of
Positioned between the bottom jaw notch edges of the side plates 77 and 78 is a spacer block shown generally at 89 which is formed of a series of vertically oriented plate laminates shown generally at 91. In the embodiment of
It is noted that the side plates 77 and 78 may be somewhat thicker than the plates forming the laminate lower block 89 or they may be of the same thickness.
As indicated in
Referring now to the embodiment of
Referring now to the embodiment shown generally at 112 in
The heavy duty structure clamp of
Another spacer block seen at 130 is spaced just to the rear of the spacer block 125 and includes a primary clearance hole 131. The block 130 includes two horizontally extending wings at the top indicated at 133 and 134 seen more clearly in
Positioned below the spacer block 130 is another spacer block 138 which includes primary tapped hole 139. The spacer block 138 includes laterally extending wings which project through slots in the wall plates and which are then coined or swaged to form the oblong rivet heads seen at 140 and 141.
With the three spacer blocks each with a primary hole spanning the side walls of the heavy duty structure clamp a rigid and low cost clamp is provided having the benefits of a cast clamp but not the problems associated with such cast clamps.
The clearance hole in the top spacer block enables a threaded rod 143 seen in
Referring now to the embodiment 150 shown in
As seen more clearly in
The spacer block 158 which is positioned over the jaw notches includes a tapped hole 171 receiving clamp screw 86 on which is mounted the locknut 87. The bottom spacer block 160 includes tapped hole 172 adapted to receive the threaded rod 173. The top spacer block 159, like the block of the
Referring to
Referring now to
The side walls are joined at the top by two spacer blocks seen at 187 and 188, both of which are provided with horizontally extending wings 189 and 190 with the ends of such wings being swaged or peened on the exterior of the walls to form the oblong heads seen at 191 and 192, respectively. The spacer block 188 is provided with the tapped hole 194 to receive the clamp screw 86 which includes the locknut 87. The clamp screw is thus positioned above the jaw opening 196 and opposite the horizontal extending portion of the bottom of the jaw indicated at 198. The spacer block 187 is supported by the wings which are coined or swaged into the oblong rivet heads indicated at 199 and includes a primary threaded hole 200 which is adapted to mesh with the threads of a vertically extending threaded rod offset or beyond any flange clamped in the jaw opening.
Positioned between the side walls at the lower part of the jaw opening is a laminated block shown generally at 204. As illustrated the laminated block includes six separate sheets or plates and the block is held in place by transverse rivet pins seen at 206 and 207. The plates forming the laminations include an upwardly extending projection indicated at 209 at the rear forming shoulder 210. The laminated block forms a strong clamping and stop surface for the flange or other structural element to which the heavy duty structural clamp is secured. The laminated block can be made and assembled in a stamping, blanking, or pressing operation more easily and at less cost than a solid block can be machined to the complex profile shape shown in
It can now be seen that there is provided a low cost light weight yet heavy duty structural clamp which may be formed by laminating relatively thin slices together. The lamination itself may be unitized by riveting, welding, bolting or peening the ends of the wings of the insert nuts or blocks to form a rivet head that locks the laminates in place. The spacer blocks may be formed from conventional T-nut shapes or can be formed from T-rail or DIN rail. It will also be appreciated that the various arrangements of the spacer blocks may vary widely as well as also the provision of either tapped holes or clearance holes. While a tapped hole is necessary for the clamp screw it is not necessary for the threaded rod since the rod may be placed through a clearance hole and held in hanging position by a conventional or slip-on nut. It may also be held by a jam-nut or a spring steel bobby pin clip.
There is thus provided a low cost light weight heavy duty structural clamp having all of the advantages of cast and machined structural clamps but none of the disadvantages.
Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification. The present invention includes all such equivalent alterations and modifications, and is limited only by the scope of the claims.