Patent Application
20050071994
This invention relates generally to a truss fabrication system for fabricating trusses, and in particular to a truss fabrication system having readily adjustable legs.
Pre-manufactured structural frameworks, such as trusses, are widely used in the construction industry for forming a roof, wall panel, floor, or other building component because of their strength, reliability, low cost, and ease of use. The trusses are typically assembled in a factory using machinery for mass-fabrication of individual truss components. The trusses are assembled, for example, on large assembly tables and then shipped to construction sites. Each truss includes a collection of typically wooden truss members held together by connectors, such as nailing plates. In assembling trusses, the truss members are arranged on truss assembly setup tables, and nailing plates having nail-like projections or teeth extending from one side are placed at the intersections of the truss members with their teeth pointed toward the surface of the truss members. To facilitate efficient assembly of the truss, a roller or gantry press is used to press the nailing plates into the truss members. The gantry press travels along the table to press the nailing plates into the truss members thereby joining them together. The roller apparatus includes a cylindric roller, roller supports, and several wheels mounted on wheel guides along opposite sides of the table. After traversing the length of the table, the roller apparatus continues moving along the guides and is stopped in a parking area at an end of the table such that the assembled truss can be freely removed from the table without obstruction by the roller apparatus.
The installation of the table gantry press tracks is critical in the proper operation of the gantry press. The truss set-up table work-surface must be level and true with respect to the gantry press to uniformly press the nailing plates into the truss members along the entire length and width of the truss. Gantry press devices of the prior art unfortunately have a number of potential difficulties. For example, initial installation of the table to a perfectly level orientation can be time consuming. Additionally, uneven settling of the ground under the truss set-up table may cause the work surface to become misaligned with the gantry press. Normally, the truss set-up table is fixedly attached to the floor, usually by welding, to prevent movement or wobble of the truss set-up table. It has often been necessary to break the welds to correct any misalignment of the table.
Among the several objects and features of the present invention may be noted the provision of a truss fabrication system having a truss set-up table which may be readily adjusted in height and adjusted to a level orientation; the provision of such a system which may be readily adjusted after the truss set-up table has been installed without disturbing the fixed attachment of the table to the floor; and the provision of such a system which reduces instability or wobble of the truss set-up table.
In general, a truss fabrication system of the invention is for fabricating trusses, each truss having at least two truss members and at least one connector for connecting the truss members. The system includes a table top defining a worksurface on which the truss members and connectors may be positioned and a gantry press which is movable relative to the table top and configured to press the at least one connector into the truss members to join the truss members. The system also includes a plurality of legs for supporting the table top at a position spaced above an underlying floor and adjustable in height such that the legs may be selectively manipulated to place the table top at a level orientation while the legs are fixedly attached to the floor. Each leg includes a leg member having a threaded opening at one end thereof and a rod having a threaded first end and a second end. The first end is received through the threaded opening such that the rod is selectively rotatable within the threaded opening to adjust a height of the leg so as to adjust the height of the table top above the floor. Each leg also includes a collar with at least one opening therein, the collar being fixedly attached to the floor. The second end of the rod is received through the opening in the collar and is rotatably movable with respect to the collar. The rod is formed to receive a tool for selectively rotating the rod to adjust the length of the leg.
In another aspect, the invention is a truss set-up table for fabricating trusses, each truss having at least two truss members and at least one connector for connecting the truss members. The set-up table includes a table top defining a worksurface on which the truss members and connectors may be positioned. The system also includes a plurality of legs for supporting the table top at a position spaced above an underlying floor and adjustable in height such that the legs may be selectively manipulated to place the table top at a level orientation while the legs are fixedly attached to the floor. Each leg includes a leg member having a threaded opening at one end thereof and a rod having a threaded first end and a second end. The first end is received through the threaded opening such that the rod is selectively rotatable within the threaded opening to adjust a height of the leg so as to adjust the height of the table top above the floor. Each leg also includes a collar with at least one opening therein, the collar being fixedly attached to the floor. The second end of the rod is received through the opening in the collar and is rotatably movable with respect to the collar. The rod is formed to receive a tool for selectively rotating the rod to adjust the length of the leg.
Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.
Corresponding reference characters indicate corresponding parts throughout the views of the drawings.
Referring now to the drawings and in particular to
The truss set-up table 12 has a plurality of parallel, elongate panels 28 providing a worksurface for placement of truss members. Slots 30 are left between adjacent pairs of panels 28 suitable for placement of conventional positioning stops (not shown) capable of being fixed along the slot to collectively form a jig for locating and holding truss members on the worksurface. The elongate panels 28 are mounted on a frame 29. The panels 28 and frame 29 form a table top supported by a plurality of legs, indicated generally at 34. The legs are adjustable in length and are fixedly attached to an underlying surface as described in more detail below. Except as further described, the set-up table 12 may be of conventional construction.
The truss set-up table 12 includes two spaced sections 36 of the table which are aligned in a row. The table may be a single section, or may include more than two sections without departing from the scope of the present invention. During operation, truss members may rest solely on one section 36, or if larger may extend across several sections. A space between adjacent sections 36 is sized for a person to walk in between the sections to set up the truss members and connectors, with a typical spacing being 15 inches. In the preferred embodiment, each section 36 has four legs. Other numbers and types of legs do not depart from the scope of this invention.
Two wheel guides 35 are securely mounted on the frame 29 opposite sides of each truss table section 36. The gantry press 14 is capable of traversing the space between the wheel guides 35 or adjacent sections 36 as it travels from one end of the table 12 to the other as set forth in U.S. Pat. No. 6,079,325. The guides 35 are provided for supporting and directing movement of the gantry press 14 relative to the truss set-up table. Each guide 35 comprises a suitably shaped elongate box beam extending generally along the table 12 and which provides tracks for engagement by drive wheels 22 and pressure wheels of the gantry press 14. For instance, in one embodiment, each guide 35 is formed of a five inch by five inch square steel beam. An upper surface of the guide 35 is generally flat and provides a track for the drive wheels 22. A lower surface of the guide 35 is also generally flat and provides a track for the pressure wheels. It is understood that there could be other types and locations of guides (including on the floor), or only one guide, without departing from the scope of this invention.
A parking area at one end of the table 12 includes a pair of stands (each designated generally at 37) aligned with and spaced from the endmost section 36 of the truss set-up table 12. The stands include guides 35 which receive the drive wheels 22 and reaction pressure wheels for supporting the gantry press 14 away from the table sections 36. After the gantry press 14 has traveled along the length of the truss set-up table 12, it moves onto the stands 37 in the parking area where it may be stopped and where it does not overlie the assembled truss so as to not interfere with removal of the truss or placement of truss members and connectors for a new truss. An additional parking area (not shown) may be provided on an opposite end of the truss set-up table.
When the motor system 26 is activated, the drive wheels 22 move the gantry press 14 until the roller 16 rolls onto the surfaces of the truss members and connectors, raising the gantry press. At that point, the drive wheels 22 become substantially unloaded, with the weight of the gantry press 14 bearing on the roller 16. The reaction pressure wheels augment a pressing force imparted by the roller 16 to the connectors (i.e., beyond the weight of the gantry press), by strongly opposing substantial upward movement of the roller 16 when rolling over truss members. The connectors are pressed into the truss members as the roller passes over them.
Referring now to
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An adjusting nut 68 is positioned on the rod 64 and affixed to the rod such as by welding so that the adjusting nut can be used to rotate the rod. Alternately, the rod 64 may be manufactured such that the adjusting nut 68 is formed as one piece with the rod without departing from the scope of the invention. Other structures (not shown) for engaging the rod 64 with a tool to effect rotation may be used within the scope of the present invention.
A lower portion 69 of the rod 64 is received through a counterbored opening 71 (
The collar 70 is fixed to an anchor plate 80 (
During initial installation of each table section 36, the rod 64 of each foot 40 is inserted through the opening 71 in the collar 70 so that the cap 74 is inside the collar 70. A smaller portion of the cap 74 fits into a smaller portion of the opening 71. The adjusting nut 68 is placed on the rod so that it rests on the upper surface 73 of the collar. In one embodiment, the adjusting nut 68 rests adjacent the collar so that any gap between the adjusting nut and collar 70 is removed but the rod 64 is still able to rotate with respect to the collar. The upper portion 65 of the rod 64 is inserted into the opening 60 to threadably engage the rod with the leg member 38. The adjusting nut 68 is suitably fixed to the rod 64, such as by welding, and the collar is fixedly attached to the floor F, such as by welding the collar to the anchor plate 80, to securely fix the foot 40 to the floor. This procedure is repeated for the other foot 40 of the leg 34, and for the feet of the other legs.
To adjust the height of the table 12, or to change the height of one or more of the legs 34 to place the table top 31 in a substantially level condition, the jam nut or nuts 66 on the leg to be adjusted are first loosened to provide a gap between the jam nut and the lower end of the leg member 38. Adjustment of the foot 40 is accomplished by rotation of the rod 64 using a wrench (not shown) received on the adjustment nut 68. As the rod 64 rotates, the leg member 38, which is threadably engaged with the rod, moves in an axial direction relative to the rod and the collar 70 on the threaded upper portion 65. The rod 64 remains in substantially the same axial position relative to the collar 70 and the anchor plate 80. For leg members 38 having two feet 40, the adjustment rod 64 for each foot is rotated either simultaneously or sequentially to adjust the height of the leg member 38. After the leg member 38 has been adjusted to the desired height, the jam nut 66 is re-tightened to secure the leg 34 at the selected height. This adjustment can be done any number of times without affecting the securement of the table to the floor.
When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
