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United States Patent m
 JIG FOR FORMING TRUSSES AND THE LIKE
 Inventor: Austin S. Weaver, 6620 - 96th Ave., Zeeland, Mich. 49464
 Appl. No.: 515,603
 Filed: Apr. 27,1990
 Int. CI.' B30B 3/02
 U.S. CI 269/37; 269/910;
 Field of Search 269/40, 37, 43, 303,
269/304, 910; 100/913; 29/281.1, 281.3;
227/152, 154, 155
 References Cited
U.S. PATENT DOCUMENTS
3,241,585 3/1966 Jureit 269/910
4,379,426 3/1983 Thompson et al 269/910
4,943,038 7/1990 Harnden .
[ii] Patent Number: 5,085,414  Date of Patent: Feb. 4, 1992
Alpine Engineered Products, Inc., New Equipment Report, Feb. 1-3, 1990, pp. 1 and 2.
Primary Examiner—Robert C. Watson
Attorney, Agent, or Firm—Varnum, Riddering, Schmidt
A jig for forming wooden trusses and like structures, including a table traversed by upwardly opening channels in which stop units are received to define the structure to formed. Each stop unit includes a stop and a clamp member which are adjustable to clamp elements of the channel between them and thereby fix the location of the stop along the length of the channel in which it is received. Each' channel carries a scale at one side and the clamp member carries an index mark to be aligned with positions on the scale for accurately locating the stop.
6 Claims, 2 Drawing Sheets
U.S. Patent Feb. 4, 1992 Sheet 1 of 2 5,085,414
JIG FOR FORMING TRUSSES AND THE LIKE
BACKGROUND OF THE INVENTION
This invention relates in general to new and useful 5 improvements in jigs, and more particularly to an improved jig for forming assemblies such as roof trusses which may vary greatly in configuration.
Wooden trusses such as roof trusses are commonly assembled on large horizontal tables supported by any 10 suitable means at working height above a shop floor. Heretofore, stops have been laid out and affixed to the table surface using tape measures and chalk lines to provide a jig setup defining the truss to be assembled. In the case of wooden table surfaces, the stops comprise 15 wood blocks nailed in place. The less-common steel surfaces are perforated to provide bolt holes spaced at six-inch intervals. Stop fixtures are bolted in place using these holes, the fixtures being adjustable to locate stops carried thereby more precisely. 20
These systems, though inefficient, have been acceptable because until recently the same jig setup was used to assemble 35 to 40 or more identical trusses in succession. Now, however, architects and builders tend to design and construct unique or "custom" residences and 25 commercial buildings with little regard for standardized roof dimensions and configurations, and it is therefore not unusual for a truss manufacturer to receive orders for as few as four or five trusses in a given pattern. In the face of such small numbers, the foregoing conven- 30 tional methods of laying out jig setups become extremely expensive procedures. Further, when a builder requires additional trusses in a given pattern after the jig setup has been removed or altered, in order to be certain that the pattern and dimensions are precisely dupli- 35 cated, it has been necessary to return one of the previously made trusses to be used as a template for reproducing the jig setup.
An expedient intended to reduce the time required for setting up truss jigs has recently been developed in 40 which recessed channels are spaced at equal intervals in parallel across the jig table surface, each channel supporting a stop at surface level, the stop being movable along the length of the channel by means of a worm drive which includes a threaded shaft extending longi- 45 tudinally within the channel. Each channel originates at an edge of the table, extending inwardly therefrom to terminate short of the opposing edge. Alternate channels originate at opposite edges. The threaded shafts are rotated by means of an air wrench to position the stops. 50 For a given truss configuration, the location of each stop along the length of the respective channel is indicated by a computer readout in terms of the equivalent number of revolutions of the corresponding threaded shaft. A meter or counter is provided at the edge end of 55 the shaft so that the operator may rotate the shafts until the counter readings are matched with the respective numbers provided by the computer readout. Such an installation is not only extremely expensive, but is necessarily limited to only a single stop per channel. 60
U. S. Pat. No. 4,943,038, issued July 24, 1990 in the name of C. W. Harnden and assigned to Alpine Engineered Products, Inc., is directed to apparatus of the foregoing description.
SUMMARY OF THE INVENTION 65
This invention facilitates and accelerates formation of a jig setup to a remarkable degree in comparison with
the prior systems. The invention provides a jig in which a plurality of upwardly open channels traverse the table at its upper surface. The channels are adapted to receive a plurality of stop units for sliding movement relative to the channels, each of the stop units being freely movable to any location along the length of the respective channel. Also included are means for releasably fixing the locations of the received stop units relative to the respective channels. Each channel is provided with a scale, and each stop unit carries index means which may be aligned with the scale to locate the stop unit accurately relative to the channel.
Although most truss configurations require only one or two stop units per channel for accurate assembly, three or more stop units per channel may be employed, to provide, for example, for accurate placement of intermediate truss members.
The jig is particularly useful in conjunction with a computer program which provides a numerical readout for positioning each stop. Thus, not only can each jig setup be achieved and adjusted rapidly, but any truss configuration may be reproduced or duplicated by simply referring to a computer printout or electronic record, which can be retained on file for each truss pattern.
These and other features, objects and advantages of the invention will be apparent from the ensuing description in conjunction with the accompanying drawings and the appended claims.
FIG. 1 is a top plan view of a truss jig in accordance with the invention, with stops located for defining a complex truss configuration shown assembled;
FIG. 2 is an enlarged perspective view from above and from an end of one of a plurality of identical channels of the table of FIG. 1 and of a stop unit carried thereby, adjacent portions of the table being omitted;
FIG. 3 is a somewhat further enlarged vertical sectional view traversing the channel of FIG. 2 and showing particulars of the stop unit carried thereby and the manner in which the channel is mounted in the table, adjacent portions of which are shown in fragmentary form;
FIG. 4 is a fragmentary top plan view of the channel of FIGS. 2 and 3 and the stop unit carried thereby; an
FIG. 5 is an exploded perspective view of the stop unit of FIGS. 2, 3 and 4.
DESCRIPTION OF THE PREFERRED
With particular reference to FIG. 1, there is illustrated a jig formed in accordance with this invention and identified generally by the numeral 10. Jig 10 includes a table 12 which may take any one of a variety of constructions, a typical example of one such construction being partially illustrated in FIG. 3. In this construction table 12 includes joists or beams, one of which is shown in fragmentary form at 14 in FIG. 3, the joists supporting the table decking in the form of panels 16 suitably comprising relatively heavy planks or plywood sections. These are secured to the joists or beams 14 by any suitable fastening means (not shown). The decking panels of table 12 may alternatively comprise suitably dimensioned metal plates or sheets. In any case, their upper surfaces lie in a single horizontal plane to form the working surface of table 12.