|Publication number||US3639962 A|
|Publication date||Feb 8, 1972|
|Filing date||Feb 11, 1970|
|Priority date||Feb 11, 1970|
|Also published as||CA942484A1|
|Publication number||US 3639962 A, US 3639962A, US-A-3639962, US3639962 A, US3639962A|
|Inventors||Gooder Robert M|
|Original Assignee||Gooder Robert M|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (1), Referenced by (10), Classifications (10)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Gooder Feb. 8, 1972  SYSTEM FOR FABRICATING STRUCTURAL MEMBERS Robert M. Gooder, 2537 Country Club Drive, Olympia Fields, lll. 6046l  Filed: Feb.1l, 1970 [2l] Appl.No.: 10,324
52 US. Cl. ..29/1ss R, 29/200 8  rm. Cl. ..B23p 17/00, 823p 10/00  Field ot'Search ..29/|55 R, 200 B, 155 c, 429,
Primary Examiner-Thomas H. Eager Attomey-E. Manning Giles, J. Patrick Cagney and Peter S. Lucyshyn  ABSTRACT An apparatus and process for completing the assembly of a joist including a support platform adapted to carry a joist in a generally horizontal orientation with a bottom chord extending along one side and a top chord extending along an opposite side, rollers carried by said support platform each having a plurality of laterally spaced recesses, ones on different rollers being generally aligned to receive said lower chord, a set of movable clamping bars located above said rollers, having laterally spaced gripping troughs adapted to cooperate with said roller recesses to selectively grip said bottom chord, two sets of laterally movable roller wheels having stationary baseplates associated therewith and being longitudinally spaced along a top chord side of said support platform, a first set positioned below or on an underside of said top chord and a second set positioned above or over said top chord, a set of clamping fingers interposed between said second set of roller wheels actuatable to engage said top chord and clamp the top chord and web together against the lower set of roller wheels, pneumatic means associated with said movable clamping bar, said first and second set of roller wheels and said clamping fingers, responsive to actuation of electrical controls firstly, to grip the lower chord, secondly, to laterally press said respective lower and upper sides of the top chord against said stationary plates, thirdly to clamp said top chord and web together, and welding means operative to weld said top chord to said web.
19 Claims, 9 Drawing Figures PATENTEU FEB 81972 3.639.962
SHEET 1 OF 6 PATENTED FEB 8 I972 SHEET 0F 6 SYSTEM FOR FABRICATING STRUCTURAL MEMBERS BRIEF SUMMARY OF THE INVENTION The present invention relates to a process and apparatus for assembling a structural member and more particularly to a process and apparatus for effectuating alignment and connection of respective longitudinally extending parts of the struc tural member. One exemplary preparation of the respective parts of the structural member which can be handled by the present invention are described in my copending application titled: Improved System for Fabricating Structural Members, Ser. No. 10,560, filed Feb. 11, I970.
The present invention is in a process and machine for assembling longitudinal parts of structural members. These structural members are bulky and difficult to handle. As one example, certain characteristics of short span steel joists are standardized for certain depth sizes, for example nominal depth sizes from 8 inches to 24 inches in 2-inch increments (see Steel Joist Institute, Standard Specifications and Load Tables, 1969 Edition). However, the present invention has been used to make 28-inch joists, and that is not an upper limit. The length, on the other hand, is made to order, for example lengths of 60 feet, though it can be greater. Multiple members must be assembled to form a structural member. For example, in a joist there may be two substantially joist-length round bars for the lower chord, two web ends and a web midsection that are joined to form a length substantially that of the completed joist, and two substantially joist-length angle bars. There are also the more easily handlable pieces such as struts, shoes and plugs. The relatively long members, that is as measured by ease of manual handling, must be assembled so that the joist meets a standard nominal depth size to within about one-eighth of an inch and the job order length to within about one-fourth of an inch even with lengths of 60 feet. For certain applications it is desirable to have a bow" or camber in the structural member so that when a load is applied and the portion of the member spanning the end supports yields, the load is held substantially level over the length of the structural member. Prior efforts toward effectuating such a camber in a structural member during fabrication have been difficult to practice and unreliable in assuring a predetermined camber, for example, three-eighths inch in a span of feet and threefourths inch in a span of 40 feet.
Accordingly, it is an object of the present invention to provide a process and apparatus for fabricating a structural member permitting the use of a continuous flow of multiple members for assembling at least two longitudinally extending parts that are then accurately aligned and permanently connected into a one-piece structural member of predetermined dimensions.
It is a more detailed object of the present invention in accordance with the above to provide a process and apparatus for fabricating of structural members which includes a sequential handling of the structural member parts, i.e., feeding, braking, locating, clamping and connecting, that permits a continuous flow of material toward and through the system at an automatically timed rate so that a predetermined machine set pace is maintained to permit accurate control of production quantity and quality.
It is yet another detailed object of the present invention in accordance with the above to provide a process and apparatus for fabricating structural members so as to shape the respective longitudinally extending parts to effect a predetermined camber in the finally formed structural member.
It is an overall object of the present invention in accordance with the above to provide a process and apparatus for fabricating structural members that is versatile and efficient, yet assuring meeting of requirements as to dimensions, shape and strength in the completed structural member.
Other objects and advantages of the present invention will become apparent from a reading of the following detailed description and upon reference to drawings in which:
FIG. 1 is a pictorial representation with portions broken away of an exemplary structural member, a joist, fabricated in accordance with the teachings of the present invention;
FIG. 2 is an end elevation of the joist of FIG. 1;
FIG. 3 is a side elevation of an exemplary final assembly machine adapted to practice the present invention;
FIG. 4 is an end elevation of the machine in FIG. 3 as viewed from the line 44 with parts in section;
FIG. 5 is a plan view of a support platform in the exemplary final assembly machine;
FIG. 6 is a partial view similar to FIG. 4 showing a detail;
FIG. 7 is a diagrammatic representation of an exemplary pneumatic system for effectuating operation of the various pneumatic cylinders throughout the machine; and
FIGS. 8A and 8B are one electrical schematic on two sheets of the system for controlling operation of the pneumatic system.
Turning to the drawings and FIGS. I and 2 in particular, there shown is an exemplary structural member, a joist 10 having a longitudinally extending intermediate member or sec tion, herein shown as a web 11, and respective longitudinally extending side members or sections, herein shown as a bottom chord 12 and a top chord 14. The web is exemplarily shown as being round steel stock formed into a zigzag or serpentine shape with a midsection l5, respective opposite ends 16, I8 and a plurality of lower and upper stress or load points 19 and 20, respectively, one being aligned along the lower periphery of the web and the other being aligned along the upper periphery of the web. The web portion between two upper stress or load points is defined as a panel, one such panel being identified by a reference character 21. In the exemplary practice of the invention, the distance between adjacent stress points has been set at a predetermined constant value for the different depth sizes of joists, that distance being 2 feet. Other distances may be used, however, for one practical instance of the use of the invention 2 feet has been found desirable.
The bottom chord I2 is exemplarily shown as comprised of two round steel bars 22, 24 connected so as to sandwich between them lower stress or load points 19 of the web. The lower chord extends the length of the joist, connecting all of the web lower load points. The top chord 14 is exemplarily shown as comprised of two steel angles 25, 26 connected on opposite sides of the upper stress or load points 20, sandwiching the web therebetween. The top chord provides a surface suitable for receiving a structural load, for example slabs of concrete forming a roof, floor or road surface or other joists, spaced and extending transversely.
To facilitate installation of the joist 10 at a job site, it may be desirable to provide shoes at opposite ends of the top chord 14. Four such shoes 28, 29, 30 and 31 are exemplarily shown.
Additional strengthening of the joist can be effected at the ends of installing respective struts 32, 34, intersecting the top chord at the next panel stress or load point. Because the material used in making the structural member is steel, welding is used as the exemplary fastening means to connect the respective components together. It is appreciated by those skilled in the art that if other materials are used then other suitable fastening means can be utilized.
As will be understood by those skilled in the art certain characteristics of several types of joists have been specified. For example, see the Steel Joist Institute, Standard Specifications and Load Tables, 1969 Edition (printed yearly). The standard joists are available in certain depth sizes, reference character 35 in FIG. 2 represents the depth dimension of a joist. The sizes start at 8 inches and go up to 24 inches, being available in 2-inch increments between these two sizes. The present invention has been used to manufacture steel joists of a depth of 28 inches, however, that is not considered to be a limit on the depth size which can be made. Within each depth size, there are designations to identify load carrying ability of different capacity joists. There are various ways to change the load carrying capacity of a joist. One way is to increase the size of the stock material from which the joist is manufactured, such as the size of the stock from which the web, bottom chord and top chord are fabricated. The present invention facilitates use of another practice for increasing the loadcarrying ability of the joist. That practice uses plugs 36 located between the respective top chord angles 25, 26 as a part of predetermined ones of the panels 21, preferably panels which are in the midsection of the joist.
The length of the joist, represented by reference character 38 in FIG. 1, is made-to-order for the particular job. As will be explained subsequently, the present method permits the fabricator to guarantee that the joist will meet the length specification to within one-quarter of an inch, which for a 40- foot span is to within about 0.06 percent. Joist can be made accurately, yet the method is sufficiently versatile to allow manufacture of joist within the aforementioned wide range of sizes.
A particular type of joist is selected as exemplary in order to describe the best mode contemplated of carrying out the present invention. It is understood, however, that other types of structural members having respective longitudinally extending parts which must be brought into registry and connected, can also be fabricated by using the present invention. An exemplary procedure useable to prepare one form of the respective structural member parts for subsequent assembly using the teachings of the present invention can be understood by reading my aforementioned copending application. However, other forms of structural members, not prepared as described in the latter, also can be advantageously fabricated using the features of the present invention as shall be understood from the description.
Turning now to FIGS. 3, 4, 5, and 6, there shown is a machine 200 for completing assembly of structural members, for example such as the joist 10. For receiving the joist, a feed platform 201 extends longitudinally from a front or mouth end 202 of the machine. As herein shown, the feed platform includes a set of transporting rollers and another set of aligning rollers. Representative of the transporting rollers is a roller 204 which extends laterally, substantially the width of the feed platform, and is supported at its respective opposite ends by longitudinally extending frame members 205, 206. That set of rollers is adapted to carry the web 11 and lower chord 14 of a structural member, and because they extend laterally can accommodate a range of structural member sizes, for example, joist widths from 12 inches to 28 inches. To assure that the lower chord moves into the final assembly machine 200 in a substantially straight line, a vertically oriented aligning roller assembly 208 is provided. The latter is selectively positionable along a laterally extending frame member 209.
For guiding one of the top chord angles, angle 25 in the present instance lying beneath the web top stress or load points 20, as the tacked together or partially connected web and top and bottom chords are moved into the machine front end 202, a set of roller wheels, one of which 210 is shown are provided along one of the sides of the platform 201,. a front side as viewed in FIG. 5. The roller wheels are rotatably supported on a frame member 211 extending longitudinally along the front side of the feed platform.
To receive the joist from the feed platform, the machine 200 is provided with a coextensive support platform 212. The latter includes a plurality of longitudinally spaced, laterally extending roller assemblies 214, 215, 216 and 217, respectively. As best shown in FIG. 4 using roller assembly 217 as an example, opposite ends, 217a, 217b of the roller are journaled in upright bearing blocks 218, 219, respectively, the latter being carried by a frame member 220 lying below each of the roller assemblies.
In order to guide the bottom chord 12 through machine 200 the roller assemblies 214217 are each provided with a plurality of annular grooves, the grooves 221 of roller assembly 217 being selected as representative. The annular grooves on the exemplary rollers are laterally spaced approximately 2 inches apart to accommodate the location of the bottom chord for standard size joists, the depth dimensions of which are selectable in 2-inch increments. Because the size or diameter of the lower chord bar stock increases as the depth of the joist increases, it will be noted that the annular grooves near exemplary roller end 2171: are deeper and wider than the annular grooves near the opposite end 217a. By being rotatable, the rollers 214-217 facilitate the movement through machine 200 of thejoist lying in a generally horizontal position. As can be appreciated by one 'skilled in the art the shape of the grooves is selected to accommodate the shape of the material used for the bottom chord. In the present instance the material is round bar stock, however various shapes usable in the structural field can be employed, for example rectangular, channel or angle stock.
The exemplary joist is received at machine 200 in a preassembled or partially assembled state. As has been explained in my copending application describing the continuous flow method for manufacturing structural members such as joists, the lower chord 12 and web 11 can be fastened together. For purposes of describing the present invention, that assembly can be referred to as a longitudinally extending structural member part 222. Feeding into the final assembly machine 200 is another longitudinally extending structural member part, in the present instance the top chord 14 including angles 25, 26, has been connected with one end of joist part 222. In the exemplary practice of the invention the joist is partially assembled at an end which first enters the assembly machine 200, referred to as the machine forward end. In the exemplary embodiment of the final assembly machine, the latter completes the connection of joist part 222 with another joist part, herein shown as top chord 14. However, it is contemplated that machine 200 can receive longitudinally extending structural member parts which have not been previously aligned and registered, and then complete assembly thereof.
For engaging and guiding the top chord 14, a plurality of roller wheel assemblies 225, 226, 227, 228, 229, and 230, respectively are disposed along a longitudinally extending side of the exemplary support platform 212. Each assembly includes one of the respective roller wheels 225a-230a and one of the respective stationary plates 225b230b. For laterally moving the respective wheels 225a-230a with respect to the plates, individual pneumatic cylinders C1, C2, C3, C4, C5, and C6 are provided, one associated with each of the respective roller wheel assemblies.
Describing the roller wheel assemblies in more detail, the assembly 230, best shown in FIG. 4, is selected as exemplary. The roller wheel 230a is carried on a shaft 231 that is slidably and rotatably journaled at its opposite ends, one end is journaled in the stationary plate or locating base member 230!) and the opposite end is journaled in a bearing 232. The latter is carried on a support 234. The roller wheel 2300 is chamfered along a peripheral edge and is adapted to engage and press an upper chord angle 25 against the adjacent or inner surface of plate 230b. For receiving the particular shape of the top chord, in the present instance a depending leg of the angle 25, the roller wheel and the base plate are spaced apart. To bias the roller wheel 230a away from the plate 230b, the exemplary structure includes a hub 233 at one end of shaft 231 enclosing and retaining a spring 233a. The spring acts against an end 231a of the shaft 231, which carries the roller wheel 230a, thereby to press the latter inwardly or to the left as viewed in FIG. 4.
For sliding the roller wheel outwardly or toward the locating plate 23% in order to press the top chord angle 25 against the plate, a rocking arm assembly 235 is provided. The latter includes a rocking arm 236 pivotally connected at its midsection 238 to support 234. One end of the arm 236 is provided with a hollowed out seat 239 to receive a rounded end 240 of shaft 231. The opposite end of rocker arm 236 also has a hollowed out seat 241 adapted to receive one end of a plunger 242 which is actuatable by, and is an integral part of, a pneumatic cylinder C6, Thus, the spring 233a will exert a force on roller wheel shaft 231, pivoting the rocker arm 236 counterclockwise as viewed in FIG. 4, to maintain the rocker arm pressed against the pneumatic cylinder plunger 242. If the pneumatic cylinder C6 is supplied with pneumatic power, the plunger 242 is extended and the shaft 231 is moved laterally against the force of biasing spring 233a, thereby pressing or locating the top chord angle 25 against the stationary plates 22512-23012.
Turning now to the structure provided above the support platform which is adapted to cooperate in locating and clamping the structural member parts feed into machine 200, there are provided a plurality of clamping bar assemblies 244, 245, 246, and 247, respectively. Associated with each of these bars for effecting generally vertical movement thereof as viewed in FIGS. 3, 4, are respective pneumatic cylinders C7, C8, C9 and C10. The clamping bar assemblies are carried on respective vertically extending frame members 250, 251, 252, and 253, respectively.
Turning to P16. 4 and describing in more detail representative clamping bar assembly 247, the latter includes a laterally extending bar 247a having one end pivotably connected on a pintle 254 carried by the frame member 253. The bar 247a extends out from the pivot pintle 254 to generally overlie the support platform 212 and to cooperate with the support platform roller assemblies, as represented by roller assembly 217, to grip the joist bottom chord. To that end, there are provided along the underside of clamping bar 247a a set of gripping troughs 255. There is a trough 255 located directly opposite each of the roller recesses 221 so as to cooperate in gripping and clamping the bars forming the bottom chord 12.
For raising and lowering the clamping bar 247a, the pneumatic cylinder C10 is mounted on frame crossarm 256. An actuatable shaft 258 depends from cylinder C10 and is connected to the outboard end of bar 247a by suitable means, a pin 259 being provided for that purpose in the exemplary embodiment. As was described of the annular grooves 221 provided in the roller assembly 217, the clamping bar troughs 255 also are fonned to accommodate bottom chord bars of larger diameter as are used in joists of greater depth, i.e., depth size of l2 inches compared to 28 inches.
To laterally locate the other part of the top chord 14, that is the upper or overlying angle 26, a set of roller wheel assemblies 260, 261, 262, and 263, respectively, are provided positioned longitudinally along one side of the support platform and above the latter. The assemblies correspond to the roller wheel assemblies 225-230 which act on the underside or lower angle 26. The assemblies include a set of roller wheels 260a-263a, a set of stationary plates 260b-263b, and a set of pneumatic cylinders C1], C12, C13, and C14. As explained, each assembly includes a roller wheel, a stationary plate and a pneumatic cylinder.
Describing roller wheel assembly 263 as representative, the roller wheel 263a is carried on a shaft 265 rotatably journaled at one end in a stationary plate or locating base member 263b and at the opposite end in a bearing block 266. The roller wheel 263a is biased away from the stationary locating plate 263b by a spring assembly including a hub 268 acting as a retainer for a biasing spring 269 acting on an end 2650 of shaft 265. For effecting lateral movement of the roller wheel 263a, a rocker arm assembly 270 is provided. The latter includes a rocker arm 271 pivotally supported at 272, having one end 273 coupled to shaft 265, and an opposite end 274 coupled to a plunger 275 operated by pneumatic cylinder C14. As has been described with respect to the roller wheel assembly 235, the actuation of pneumatic cylinder C14 pivots rocker arm 271 and moves shaft 265 against the action of spring 268. As a result, the roller wheel 263a is moved laterally against plate 263b, thereby pressing the uppermost or overlying angle 26 against the stationary locating plate. Thus, with the respective roller wheels 225a-229a acting on the underside angle, and the roller wheels 260a-263a acting on the overlying angle, the top chord 14 is moved laterally with respect to the bottom chord 12 and located so as to assure an accurate depth for the structural member being fabricated.
Structural members of different size may use different size materials for the top chord angles 25, 26 and also for the web 11 thereby resulting in variations in a dimension M as viewed in FIG. 4. To provide a vertical adjustment for the roller wheel assemblies 260-263 to accommodate the different size materials, suitable means may be provided on a frame head beam 277.
Summarizing the operation of the aligning and gripping structures described above, the bottom chord 12 is first gripped between the roller assemblies 214-217 and the clamping bar assemblies 244-247. Subsequently, the top chord 14 is laterally located by roller wheels 225a-230a positioned to engage the lower angle 25 and roller wheels 260a-263a positioned to engage the upper angle 26. 1n the exemplary embodiment the roller wheel assemblies act to laterally move the respective angles 25, 26 of the top chord 14, and additional means are provided to sandwich together the top chord and web.
To complete the assembly of the structural member part 222 (bottom chord and web) and the other structural member part, herein represented by top chord 14, it is necessary to bring into intimate engagement or sandwich together the respective angles 25, 26 and the interposed portion of the web 11. To this end, in the present instance a plurality of clamping or pressing assemblies 278, 279, 280, and 281, respectively, are provided. The latter assemblies include respective fingers 278a, 279a, 280a, and 281a, which are actuated by associated pneumatic cylinders C15, C16, C17, and C18, respectively. The clamping finger assemblies 278-281, disposed above the support platform, in the present instance are mounted with the upper roller wheel assemblies. As herein shown the clamping finger assemblies are located adjacent one of the upper roller wheel assemblies 260-263. Thus, when pneumatic power is provided to the cylinder C15-C18, the respective fingers are actuated downwardly so as to press the upper or overside angle 26 against the web 11 and the underside or lower angle 25 carried by the roller wheels 225a-230a. As subsequently explained, the individual structural member parts 222 and 14 are fed into machine 200 and braked, to locate lower stress or load points 19 between the roller assemblies 214-217 and the clamping bars 244-247, and to locate the upper stress or load points 20 between the lower roller wheel assemblies 225-229 and the clamping finger assemblies 278-281 (see FIG. 5).
It is a feature of the present invention that the structural member is accurately sized and clamped, prior to fastening of the respective parts, in the present instance the top chord 14 and the structural member part 222. Any suitable means of fastening may be utilized to permanently connect the respective members together. It has been found in practice that where steel joists are being fabricated, arc welders having automatic wire feed of the type manufactured by the Lincoln Electric Company have given good results. Depending on the materials which are being used to fabricate the structural member, appropriate fastening means may be used to complete the assembly.
To feed out of draw succeeding lengths of the joist located on the feed platform 201, a suitable feed mechanism is provided. In the present instance, a traveling beam assembly 284 (see FIG. 4) is employed. The latter includes a traveling beam 285, exemplarily shown as an l-beam which is slidably carried by suitable means, for example a set of longitudinally positioned trunnionlike rollers 286, 288. Though only an upper set of rollers, as represented by roller 286, is shown extending toward a web section 289 of l-beam 285 from one side, and only a lower set of rollers, as represented by roller 288, is shown extending toward the web from the opposite side, there would be another set of lower and upper rollers respectively, extending toward the web located opposite the rollers shown. The rollers are vertically spaced apart so as to fit between the top and bottom sections of the l-beam and thereby provide a suitable track to permit longitudinal, back and forth movement of the beam.
To longitudinally actuate the traveling beam 285, in the exemplary embodiment a long stroke pneumatic cylinder C19 is provided. In one practical application, the cylinder C19 has a stroke of 8 feet. To selectively engage the structural member part 222, in the exemplary embodiment the traveling beam 285 is provided wit 21 depending finger mechanism 290 (see FIG. 3). The finger mechanism 290 engages the web 11 in a generally defined portion of web 11 so as to bring the structural member into machine 200 wit the respective stress or load points 19, 20 located as previously described relative to the clamping mechanism. The purpose is to assure that clamping is donewhere a full width of material is gripped rather than where a void of material maybe present as between the stress points. I
Explaining the operation of the traveling beam assembly 284 as viewed in FIG. 3, pneumatic power may be applied to cylinders C19 to effect longitudinal movement of the beam 285 to the right. The beam travels out over the feed platform 201 and finger mechanism 290 is brought into engagement with a web portion 11 of the structural member part 222. Pneumatic power is then applied to the cylinder C19 so as to effect movement of the traveling beam 285 to the left. As a result the respective structural member parts 222, and top chord 14, are moved longitudinally to the left and into the final assembly machine 200 onto the support platform 212.
It is another feature of the present invention that a predetermined camber or offset can be incorporated into the structural member during the final assembly operation. As best illustrated in FIG. 5, the feed platform 201 directs the structural member parts into the machine receiving end 202 in a substantially straight line orientation. Provided at the machine input 202 is a vertical roller 203 journaled at its respective upper and lower ends in the machine frame and adapted to engage one side of the structural member. The sizing and clamping mechanisms within the machine 200, already described, are offset in a graduated manner with respect to each other. Accordingly, a portion of the structural member fed onto the support platform 212 is bent with respect to the portion of the structural member extending between vertical rollers 203 and 208, Le, the portion of the structural member still to be fed into the machine.
To describe the mechanism for effecting the camber, only the portion of the mechanism associated with the support platform 212 is shown. Of course, the sizing and clamping mechanisms cooperating with the support platform and overlying it would be complementarily located to act in conjunction with the mechanisms in the support platform 212 in order to size and clamp the structural member during the connecting or fastening step to permanently impart the desired camber in a structural member.
The respective grooved roller assemblies 214, 215, 216, 217 are offset with respect to each other in a graduated manner so as to bend the lower chord 14 toward the front or bottom of the support platform as viewed in FIG. 5. As shown in the exemplary roller assembly 217 of (FIG. 3) a set of adjusting bolts 291, 292 are provided to permit lateral setting of the roller assembly 217 to effect the desired offset. In one practical application where the web panels were 2 feet in width, the respective roller assemblies 214-217 were located on approximately 2-foot centers, and were offset laterally with respect to each other in a graduated manner by one-sixteenth of an inch.
On the opposite side of the horizontally oriented structural member the respective roller wheel assemblies 225-229, also located on approximately 2-foot centers, are in a like manner offset with respect to each other in a graduated manner. Accordingly, the respective opposite sides of the structural member, as exemplarily represented by a bottom chord 14 and a top chord 12, are shaped to have a predetermined camber, for example, three-eighths inch to a span of 20 feet. It has been found in practice that for manufacture of steel joists having open webbing with respective bottom and top chords, a predetermined length of the steel joist must be fed into the final assembly machine 200 in order to effect a pennanent camber in the joist. It has been found that a 4-foot section of the joist, wherein 2-foot panels are involved, is not sufficient to assure that the camber will be retained by the finished joist. However, a 6-foot section gripped in the machine has worked satisfactorily. In the exemplary machine, an 8-foot section is fed into the machine. An exit or transporting platform 294 is curved slightly away from the front of the machine to accommodate the camber incorporated in the fabricated structural member.
It is a further feature of the present invention that the foregoing mechanical operations of the final assembly machine are centrally controlled and can be selectively operated manually in any desired sequence or operated automatically in a prearranged sequence. It is a feature of the present invention that in the automatic mode the rate of movement of the structural member parts through the machine can be set after predetermined tests. Thereafter, the machine 200 operates according to the present timed cycle providing sufficient time to effect a good quality connection between the structural member parts, yet move the parts through the machine at a suitable production rate.
FIGS. 7, 8A and 8B show exemplary pneumatic and electrical control circuits for operating the machine 200. Turning first to FIG. 7 and the exemplary power system for effecting the mechanical movements, a supply of air pressure 300 is connected through a supply line 301 to respective solenoid operated pneumatic valves. Describing these valves and identifying the machine elements they operate, valves 302,
304 control operation of the traveling beam cylinder C19, a 1
valve 305 controls actuation of the bottom chord clamping cylinders C7-C10, a valve 306 controls actuation of the roller wheel actuating cylinders C1-C6 and C11-C14, and a valve 308 controls the actuation of top chord clamping finger cylinders ClS-C18. The cylinders are in general, either of the type having pneumatic connections at opposite ends, each connection capable of directing air pressure into the cylinder or permitting air pressure in the cylinder to escape or be relieved (see schematic showing of cylinders C7 and C19). The other type of cylinder has one opening through which pressure is both introduced and relieved. In that type of cylinder the piston head associated with the cylinder actuating rod is spring biased in one direction (see the schematic representation of cylinder C11). Though a pneumatic system is described as being used in the exemplary embodiment, other actuating systems, hydraulic or electrical for example, can also be advantageously employed.
Turning now to the electrical diagram of FIG. 8A and 8B, the control circuit is energized from a pair of electrical power source lines 309, 310. To initiate operation of the final assembly machine 200, a reset pushbutton 311 is actuated to complete an energizing circuit for relay R1. Energization of the latter closes holding contacts CRla, and power connecting contacts CRlb, CRlc. The system is now ready to operate and a systems ready indicator light 312 is operated.
To initially load the structural member parts onto the machine support platform 212, a beam left pushbutton 314 is operated. As a result, a solenoid SIa is energized and the three-position pneumatic valve 302 is operated.
Turning to FIG. 7 which shows the valve, the latter includes a midportion 3020 having a pair of passages and end portions 302b and 3020, respectively, each having a pair of passages. The valve 302 normally assumes a position whereby the valve portion 302a connects the pressure input line 301 to both ends of the cylinder C19. Energization of valve solenoid Sla slides valve portion 30212 to the right as viewed in FIG. 7 thereby connecting the right end of cylinder C19 to the pressure input line 301 and connecting the left end of cylinder C19 to an exhaust conduit 315. As is clear from the pictorial representation, an input of pressure at the right end of cylinder C19 will effect movement of a cylinder piston and rod 316 toward the left. The piston and rod 316 is connected by suitable means to traveling beam 285, and as shown in FIG. 3 is operative to effect leftward movement of the traveling beam. As explained the depending finger mechanism 290 of the traveling beam engages the structural member part 222 and draws the structural member to the left and into the machine 200. The traveling beam continues its movement of the left drawing or loading a predetermined length of the structural member into the machine, until a limit switch LS1 is actuated.
The limit switch LS1 has a movable contact 318 and respective stationary contacts 319, 320, engagement of the movable contact 318 with either of the stationary contacts completes a circuit through those stationary contacts. In the present instance, the movable contact 318 is normally positioned so as not to contact either of the stationary contacts. When the traveling beam 285 reaches its extreme left-hand position as viewed in FIG. 3, the movable contact 318 is brought into engagement with the stationary contact 319 resulting in energization of relay R5. Energization of the latter opens contacts CRSa and closes contacts CRb. There are other contacts CRSc that are closed and their function will be explained subsequently. In the exemplary embodiment the relay R5 is a latching relay, which once energized, maintains its associated contacts in the actuated position, until another relay is energized to return the contacts to the opposite or deactuated position.
As can be understood from viewing the circuit, after the traveling beam 285 moves left actuating limit switch LS1, contacts CR5a are opened, deenergizing valve solenoid Sla, and contacts CRSb are closed, energizing valve solenoids Slb and S2. The effect of deenergization of valve solenoid Sla and energization of valve solenoid Slb is to slide valve portion 302a to the left as viewed in FIG. 6, and connect the pressure input to the left-hand side of cylinder C19 and the exhaust conduit 315 to the right side of cylinder C19. To retard or slow down the movement of piston and rod assembly 316 as it travels to the right, the solenoid S2 acts on valve 304 to slide a valve portion 304a out of registry with exhaust conduit 315 and bring a valve portion 304b into registry with the latter. As a result, a restrictive passage 321 is thereby connected into the exhaust conduit 315 to effect a limitation on the air flow from the right-hand side of cylinder C19, thereby retarding the speed of the traveling beam 285 as it moves out and over the feed platform 201. To stop the traveling beam 285 when it reached its fully extended position, the limit switch LS1 is again actuated and movable contacts 318 close contacts 320 and energize relay coil LR 5 which functions to unlatch relay R5. The result is, contacts CRSa are returned to a closed position and contacts CRSb are returned to an open position. The latter deenergizes valve solenoid Slb and S2 thereby causing the central portion 302a of valve 302 to connect with the cylinder C19 and stop the travel of the piston and rod 316.
At this point the structural member has been loaded into the machine 200 and has a portion resting on the support platform 212. To continue operation of the machine, a manual-automatic selector switch 322 having contacts 322a, 322b, and 3220 is operated to automatic." To indicate that the control system is in automatic, an indicator light 324 is provided. Next, a cycle pushbutton 325 is operated. First, a relay R3 is energized closing contacts CR3a, CR3b. Closing of contacts CR3a initiates the sizing and clamping of the structural member, while closing of contacts CR3b contributes to subsequent energization of a timer motor TM1. The operation of latter is explained subsequently.
First, closing of contacts CR3a completes an energizing circuit to time delay relays TDR2, TDR3, and TDR4. The latter are preset to actuate their respective contacts CDR2, CDR3, and CDR4, after predetermined periods of time have elapsed. Thus, after a selected time delay, for example, 1 second, contacts CDR2 are closed and valve solenoid S3 is energized. Energization of the latter causes portion 305a of valve 305 to move out of registry with a set of conduits 326, and a portion 305b of the valve 305 to move into registry with the latter conduits. As a result, pneumatic pressure is transmitted through supply conduits 301 to the respective cylinders C7-C10. As has already been described, these cylinders are connected to the clamping bar assemblies 244-247, respectively, and actuation of the cylinders causes the clamping bars to be moved downwardly as viewed in FIGS. 3 and 4 to clamp the bottom chord 12 against the roller assemblies 214-217.
The bottom chord being clamped, the respective angles 25, 26 of the top chord 14 can be located with respect thereto in order to size the structural member 10. To this end, following clamping of the bottom chord a sufficient time delay is provided by relay TDR3 before actuating its contacts CDR3 and energization of the valve solenoid S4. Upon energization of the latter, a portion 306a of pneumatic valve 306 is moved out of registry with a conduit 328 and a portion 306b is brought into registry with the latter conduit. The effect is to connect the cylinders Cl-C6 and Cl1-C14 with the pneumatic supply conduit 301. These cylinders effect a lateral movement of the lower and upper roller wheels respectively to press the respective top chord angles 25, 26 against the plates associated with each of the roller wheels.
Once the structural member is properly sized, the respective longitudinally extending parts must be clamped. To this end, after a further time delay the relay TDR4 closes contacts CDR4 to energize valve solenoid S5, Energization of solenoid S5 effects movement of a valve portion 308a out of registry with a set of conduits 329 and a portion 30% of the valve 308 into registry with the latter conduits. The result is to transmit pneumatic power from the supply line 301 to the pneumatic cylinders ClS-Cl8. As has been explained, each of these are associated with respective clamping fingers 278a, 279a, 280a, and 281a. The fingers are moved downwardly to press together the respective angles 25, 26 and the web 11 interposed between the angles.
At this time the structural member is sized, clamped and ready for the fastening operation. As explained, arc welders with an automatic wire feed system have been used, and the web is welded to the respective top chord angles at each of the load points 20. An exemplary weld is shown in FIG. 4 at 330. To provide a preset period of time for holding the structural member in a clamped condition while the fastening operation is conducted, the aforementioned timer motor TM1 is provided. The timing cycle is initiated when a pressure switch PS1 connected to a pressure input one of the lines 329 associated with the pneumatic cylinders ClS-C 18 is operated. These are the clamping finger actuating cylinders and thus are the last to be operated. (See FIG. 7.) The exemplary timer motor TM1 includes a clutch coil 331 which is first energized and starts the running of the preset period of time. At the end of the time period, the motor TM1, in the exemplary embodiment is set to close contacts TM 1a, TMlb, and TMlc. The contacts TMlc control the operation of timer motor TM1 to assure that the contacts TM 1a and TMlb are opened or returned to their normal state after a sufficient period of time has elapsed to effect the desired circuit operations. Contacts TM 1a effect release of the structural member, so that contacts TMlb can initiate movement of a subsequent section of the structural member into the machine. Starting with contacts TMla, when the latter are closed, relay LR3 is energized. Energization of LR3 unlatches the contacts associated with relay R3. That results in the opening of contacts CR3a which removes energization to the time delay relays TDR2, TDR3, and TDR4, thereby opening their respective contacts and deenergizing solenoids S3, S4, and S5. The valves 305, 306, and 308, thus, assume a normal position in which the pneumatic cylinders associated with each of the valves are actuated to retract respective clamping or pressing mechanism. The structural member is thereby freed so that it can be moved longitudinally over the support platform 212.
To indicate the end of the welding cycle, if it is desired, a bell 332 may be provided. The operation of the latter is effected by a timer motor TM2. The latter includes a clutch coil 334 which initiates the timing operation of the timer motor TM2, and it is energized at the same time that timer motor TM1 is energized (see FIG. 8B). The timer motor TM2 includes a pair of contacts TM2a, TMZb. With the closing of contacts TM2a the circuit to bell 332 is completed, and the bell is rung, while closing of contacts TMZb, assures the return of the timer motor contacts to their rest position after a sufficient period of time has elapsed to ring the bell 332.
The closing of contacts TMlb energizes relay R4 and closes contacts CR4 to complete the circuit to solenoid 510. As has been described, energization of the latter effects a leftward movement of the traveling beam 285 as viewed in FIG. 3 and brings into the machine 200 a subsequent portion of the structural member 10.
in the automatic operation of this system it is desirable to apply a brake to the movement of the structural member as it rolls over the support platform 212. To this end, when the manual-automatic pushbutton 322 is in the automatic position, the operation of limit switch LS1 and closing of contacts 319 energizes relay R5. The result is that contacts CRScare operated to complete a circuit both to a time delay relay TDRS having contacts CDRS and to a relay R6. The energization of relay R6 is explained first, it has a set of contacts CR6a, CR6b, CR6c, and CR6d. The effect of operation of contacts CR6c is next described. As disclosed in FIG. 8A, closing of contacts CR6c energizes relay R7 and thereby operates contacts CR7a, CR7b. Operation of those contacts energizes valve solenoids S3 and S4, respectively. The effect of energization of the latter has been explained. Reviewing the explanation, solenoid S3 operating valve 305 effects clamping of the bottom chord and solenoid S4 operating valve 306 effects lateralmovement of the roller-wheels and applies a clamping action on the top chord angles 25, 26. The foregoing clamping is a momentary occurrence to stop the inertial movement of the structural member. The energization of valve solenoids S3 and S4 is removed after a predetermined period of time by the operation of a time delay relay TDRl which was energized when contacts CR6a were closed. That time delay relay has contacts CDRl which are nonnally biased in the closed position, however, after the predetermined time delay they are opened and, being in the same circuit as relay R7, deenergize that relay to open contacts CR7a and CR7b.
Describing the clamping and sizing of the new, or subsequent portion of the structural member that is brought onto the support platform 212, because relay R is a latching relay, the contacts of relay R5 after being actuated for the braking action, remain in the state which they assumed when the relay was energized. Accordingly, contacts CRSc remain closed and maintain an energizing circuit for relay R6. The effect of the latter is that contacts CR6d are closed and an energizing circuit for relay R3 is maintained. in the Automatic" mode the contacts CR6d substitute for the cycle pushbutton 325 to energize relay R3. Energization of the latter has already been explained. it effects the sequential clamping of the bottom chord, then the sizing of the top chord and subsequently the clamping of the top chord. The energization of relay R6 has been explained in part. In addition, the following operations are effected by energization of that relay: Contacts CR6b are closed to energize unlatching relay LR4. The result is to return contacts CR4 to an open position so that the traveling beam 285 upon reaching its fully extended position does not immediately act to pull into the machine another section of the structural member.
To assure that the relay R3 is deenergized and can be unlatched at the end of the fastening or welding cycle, it is necessary to insure that the circuit to relay R3 is broken, even if the traveling beam has not reached its fully extended position at the end of the fastening cycle. To this end, a time delay relay TDRS having contacts CDRS is provided. The operation of that time delay relay is initiated when contacts CRSc are closed. After a predetermined period of time, contacts CDRS are opened and as a result relay R3 is deenergized. The foregoing timing cycles can be set for a predetermined number of seconds, depending upon the fastening procedure necessary to obtain the desired connection, and only a person in charge can change the time period. That feature makes the present invention particularly useful in incentive pay-type of assembly line operations.
It is yet another feature of the present invention that an emergency stop is provided operative to shut down the whole system, in the present instance responsive to operation of an emergency stop push button 335. Actuation of the latter energizes relay R2 and operates contacts CRZa, CR2b, CRZc. These respective contacts are individually connected to relays LR3x, LR4x, and LRSx which upon energization are operative to unlatch the contacts of each of those numbered relays. Unlatching of those relays will shut down the whole system quickly.
The present system is versatile in that it provides for selective manual operation of various parts of the system. For example, respective pushbuttons 336, 338, and 339 are provided in the individual circuits of valve solenoids S3, S4, and S5, respectively. Thus, each of these solenoids can be individually operated and the mechanism associated wit these solenoids can be actuated.
If a particular type of structural member requires complete manual operation of the machine 220, the manual-automatic pushbutton 322 may be left in a manual state and the various mechanical parts of the system can be individually operated. To this end, there is provided a pushbutton 340 actuatable to energize valve solenoids Slb, S2 to effect movement of the traveling beam 285 to the right.
As is clear from the foregoing description, the present inventive machine and process permits easy handling of structural members which have a substantial length and need to be fitted together and fastened. The machine and method provide for accurate sizing of the finished structural member in a transverse dimension and can handle structural members of all lengths as the structural member is fed-longitudinally through the machine and is handled longitudinally in the process. In addition, the present apparatus and methods permits shaping of the finished product to provide a curvature or camber in it. These desirable results are obtained in an economical and relatively simple manner.
I have described my invention in connection with an exemplary apparatus and process, it is to be understood that this is by way of illustration and not by way of limitation and the scope of my invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit.
1. In a machine for assembling a longitudinally extending structural member having first and second longitudinally extending parts, the combination comprising a feed platform for receiving said structural member; a support platform coupled to said feed platform adapted to carry the structural member within the machine; means associated with said support platform adapted to grip the first longitudinally extending part; means associated with said support platform adapted to locate the second longitudinally extending part in predetermined relationship with respect to the first longitudinallyextending part; and means for clamping the first and second structural member parts; said locating and clamping means positioning the second longitudinally extending part so that the latter can be connected with the first longitudinally extending part.
2. In a machine for assembling a longitudinally extending structural member having first and second longitudinally extending side sections and an intermediate section, the first side section being connected with the intermediate section and the second side section being adapted to be connected thereto, the combination comprising a feed platform for receiving said structural member; a support platform coupled to said feed platform adapted to carry the structural member within the machine; means associated with said support platform adapted to grip the first longitudinally extending side section; and means associated with said support platform adapted to locate and clamp the second longitudinally extending side section in predetermined relationship with the intermediate section; said locating and clamping means positioning the second longitudinally extending side section and the intermediate section so that the latter can be fastened together.
3. The combination of claim 2 including a feed mechanism for moving the structural member onto said support platform.
4. The combination of claim 3 including a control means for sequentially actuating said gripping means, and said locating and clamping means; and responsive to said fastening means completing the connection of said second longitudinally extending section and the intermediate section to release said gripping, locating, and clamping means and actuating said feed mechanism to feed onto said support platform a succeeding length of the structural member.
5. In a final assembly machine adapted to receive a joist having respective top and bottom chords and a web, the bottom chord being completely connected with the web, and the top chord being aligned and partially connected with the web; the combination comprising a feed platform for receiving the joist, a longitudinally extending support platform coupled to and coextensive with said feed platform, means associated with said support platform having longitudinally extending guides for engaging one of said chords; means disposed opposite said support platform means being complementarily shaped and selectively operable to press said engaged chord against said platform means; a first means positioned along one side of said support platform adapted to engage the other chord as the latter is moved longitudinally, said first platform side means being complementarily shaped and selectively operable to engage one portion of the other chord; a second means positioned along said one support platform side and being complementarily shaped and selectively operable to engage another portion of the other chord; stationary means associated with each of first and second means positioned to define the shape of the top chord and adapted to provide a base against which each of said means can press a predeter' mined portion of the other chord; clamping means operable to maintain the aligned and registered other chord and web intimately engaged; actuating means responsive to operation of a control means associated with said one chord pressing means, said respective first and second other chord engaging means, and said clamping means for selectively operating each of the latter; and means for connecting the top chord to the web to complete the assembly of the joist.
6. In a structural member assembly machine adapted to receive a joist having respective top and bottom chords and a web, the bottom chord being completely connected with the web; the combination comprising a feed platform for receiving the joist; a longitudinally extending support platform coupled to and coextensive with said feed platform; longitudinally spaced means on said platform adapted to engage and guide the bottom chord as the latter moves over said support platform; means disposed opposite said platform means selectively operable to engage the bottom chord and press the latter against said platform means; means positioned along one side of said support platform adapted to engage and guide the top chord as the latter is moved longitudinally, said platform side means being complementarily shaped and selectively operable to engage and locate the top chord laterally in respect of the bottom chord; and clamping means positioned along said platform side operable to maintain the located top chord and web intimately engaged for connecting the top chord to the web to complete assembly of the joist.
7. The combination of claim 6 wherein said longitudinally spaced means on said platform are adapted to guide the bottom chord in a generally bowed path; said means positioned along one side of said support platform adapted to guide said top chord along said path substantially parallel to that of the bottom chord; said means operative to clamp a predetermined length of the top and bottom chord and web in a generally bowed Orientation so that subsequent to fastening said joist length retains a predetermined camber.
8. The combination of claim 6 including means for sequentially actuating said bottom chord pressing means, said top chord locating means and said top chord clamping means.
9. The combination of claim 7 wherein said actuating means includes means for momentarily actuating said bottom chord pressing means and said top chord locating means to brake the movement of the structural member prior to initiating said sequence.
10. In a final assembly machine adapted to receive a joist having respective top and bottom chords and a web, the bottom chord being completely connected with the web, and the top chord being aligned and partially connected with the web; the combination comprising a feed platform for receiving the joist; a longitudinally extending support platform coupled to and coextensive with said feed platform; a set of laterally extending rollers provided on said platform and spaced apart longitudinally; said rollers having laterally spaced recesses aligned and complementarily shaped to engage the bottom chord as the latter moves longitudinally over said support platform; a set of laterally extending clamping bars disposed opposite said rollers and having troughs complementarily shaped and selectively operable to engage the bottom chord and press the latter against said rollers; a first roller wheel assembly positioned along one side-of said support platform adapted to engage the top chord as the latter is moved longitudinally, said roller wheel assemblies being complementarily shaped and selectively operable to engage the underlying portion of the top chord; a second roller wheel assembly positioned along said one support platform side and being complementarily shaped and selectively operable to engage the overlying portion of the top chord; stationary means associated with each of said roller wheel assemblies positioned to define the shape of the top chord and adapted to provide a base against which each roller wheel can press a predetermined portion of the top chord; a set of clamping fingers operable to maintain the aligned and registered top chord and web intimately engaged; and actuating means responsive to operation of a control means associated with said set of clamping bars, said respective sets of roller wheel assemblies and said clamping fingers for selectively operating each of the latter to hold the top chord for completing assembly of the joist.
11. The combination of claim 10 wherein said roller recesses and said clamping bar troughs are located a predetermined distance from said roller wheel assemblies and adapted to accommodate joists of predetermined depth sizes.
12. In a method for assembling a longitudinally extending structural member having respective first and second longitudinally extending parts; feeding out a predetermined length of the respective first and second longitudinally extending parts; gripping said predetermined length of the first longitudinally extending part; locating said predetermined length of the second longitudinally extending part precisely with respect to the predetermined length of the first longitudinally extending part; clamping the precisely located engaging portion of the,
respective first and second longitudinally extending parts; and fastening the clamped portions to form an integral one-piece structural member.
13. The method of claim 12 wherein after said step of feeding out a predetermined length of said first and second longitudinally extending parts there follows a step of braking the movement of said parts to locate a predetermined length of the latter in position for final assembly.
14. The method of claim 12 including the step of releasing said predetermined length of the first and second longitudinally extending parts that has been fastened in preparation for finally assembling a succeeding length of the structural member.
15. In a method for assembling a longitudinally extending structural member having respective first and second longitudinally extending parts adapted to have engaging portions substantially in registry and alignment; the steps of feeding out a predetermined length of the first and second longitudinally extending parts while supporting the remaining length; clamping said predetermined length of the first longitudinally extending part so as to bow the latter in respect of said remaining length of the first longitudinal part; locating said predetermined length of the second longitudinally extending part so as to bow the latter to have the same configuration as the bowed portion of said first longitudinally extending part; clamping together the portions of said first and second longitudinally extending structural member parts adapted to be engaged; fastening said engaging portions at selected points; and repeating the above steps so that the completed structural member has a predetermined camber as viewed from one end of the structural member to the other.
16. ln a control system for a structural member assembly machine having a feed mechanism, a clamp mechanism for a first longitudinally extending part, a locating mechanism for a second longitudinally extending part and a clamp to sandwich together the engaging portions of the respective longitudinal parts; the combination comprising first operative means for actuating the feed mechanism to draw a predetermined length of the respective first and second longitudinally extending parts into the machine; second operative means for actuating the mechanism for clamping the first longitudinally extending part and holding the latter; third operative means for actuating the mechanism for locating the second longitudinally extending part; and fourth operative means for actuating the mechanism for clamping together the first and second longitudinally extending parts respectively.
17. In a control system as set forth in claim 16 wherein the combination includes emergency stopping means to release all mechanisms at any point in the sequence of operation.
18. In a control system as set forth in claim 16 wherein the combination includes a brake operating means for actuating and releasing the mechanism for clamping the first longitudinally extending part and one of the respective mechanisms for locating and clamping the second longitudinally extending part to brake movement of the respective parts after said predetermined length has been moved, and means for releasing each of said second, third, and fourth operative means and initiating operation of said first means to load a subsequent predetermined length of the first and second longitudinally extending parts into the machine.
19. The control system of claim 16 wherein the combination includes a time delay means preset to provide a predetennined period of time between the operation of said second actuation means and said third actuation means, and the operation-of said third actuation means and said fourth actuation means.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3349468 *||Sep 8, 1965||Oct 31, 1967||Schloemann Ag Fa||Method for arresting a mandrel and tube discharged from a rolling mill|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4748786 *||Aug 17, 1987||Jun 7, 1988||Hannah William J||Fabricated open web steel joist, and manufacture thereof|
|US4836436 *||Jan 19, 1988||Jun 6, 1989||Gerald McDonald||Method of manufacturing a fabricated open web steel joist|
|US5123587 *||Jun 11, 1991||Jun 23, 1992||Owen Joist Corporation||Method and apparatus for making steel joists|
|US6886251 *||Mar 11, 2002||May 3, 2005||Vp Buildings, Inc.||Beam fabrication system|
|US8407966||Sep 14, 2009||Apr 2, 2013||Ispan Systems Lp||Cold-formed steel joist|
|US8726606||May 17, 2007||May 20, 2014||Paradigm Focus Product Development Inc.||Light steel trusses and truss systems|
|US8943776||Mar 15, 2013||Feb 3, 2015||Ispan Systems Lp||Composite steel joist|
|US8950151||Sep 8, 2009||Feb 10, 2015||Ispan Systems Lp||Adjustable floor to wall connectors for use with bottom chord and web bearing joists|
|US20050108978 *||Nov 25, 2003||May 26, 2005||Best Joint Inc.||Segmented cold formed joist|
|US20060053732 *||Jan 7, 2003||Mar 16, 2006||Watson Dennis P||Cold-formed steel joists|
|U.S. Classification||29/897.31, 29/714, 29/787|
|International Classification||B23K11/00, B21D47/00, B21D47/04|
|Cooperative Classification||B21D47/04, B23K11/008|
|European Classification||B21D47/04, B23K11/00F10|