US3234841A - Gusset plate - Google Patents

Description

Feb. 15, 1966 J. D. ADAMS 3,234,841

GUSSET PLATE Filed May 9, 1963 INVENTOR. James D. A dams ATTORNEYS Patented Feb. 15, 1966 3,234,841 GUSSET PLATE James D. Adams, Colorado Springs, Colo., assignor, by mesne assignments, to J. D. Adams Co., Colorado Springs, Colo., a corporation of Colorado Filed May 9, 1963, Ser. No. 279,258 1 Claim. (CI. 85-13) This invention relates to metal connector plates or gussets for connecting wooden structural members together, and particularly it relates to metal connector plates having a plurality of punched out teeth from each of a plurality of holes.

Structural members of wood still constitute one of the very large segments of all types of construction, and in particular wooden members are widely used as structural framing members. Metal gusset plates of all sorts are used in all types of wooden framing to provide an economical yet high strength structural assembly (sometimes called components such as root trusses, walls, wall components, panels, and the like). Various types of these metal gusset plates are available commercially, one such plate being the subject matter of Us. Patent No. 3,052,149 by Paul D. West, and assigned to Truss PreF-ab, Inc. Metal gusset plates have been found useful where the load is essentially compression, but very little information is available for the strength of such metal plate joints in tension.

Generally speaking, the relative effectiveness of such metal plate connectors is determined by a number of variables which includes the length of time which the metal plate has been in the structural member, the magnitude of forces involved, the area covered by such metal plates, the number of teeth, the amount of deformation which might be tolerated, etc. One widely used connector consists of a thin metal plate having teeth punched out in a series of single tooth punches uniformly spaced and uniformly faced in one direction. Such a plate shows a definite directional weakness since the teeth tend to bend when strained in their flat position.

According to the present invention, I have provided an improved connector plate or gusset of increased strength and holding power which is nondirectional in its strength and which requires fewer nails for securing the gusset to a wooden structure member. The device of the invention is a relatively thin metal sheet from which are punched a plurality of generally triangular teeth, there being 4 teeth punched from a single hole, and a plurality of such sets of teeth punched from the plate extending in one direction from the plate. Each tooth is provided with a longitudinal crease running from the base to the ti to strengthen the material and prevent bending of the tooth once formed. The material around each hole is creased or embossed with an annular ridge to provide increased strength of the base of the tooth. The teeth may be rotated from row to row so that adjacent teeth are arranged at a d iiferent angle, penetrating the grain of the wood at different angles thereby preventing splitting of the wood. The ribbed holes are, also, provided with a network of ribs extending from hole to hole thereby increasing the strength of the plate itself to prevent bending thereof. Included among the objects and advantages of the present invention is a metal connector plate having a plurality of sets of teeth punched from the plate, and each set of teeth being punched from a single hole with each tooth provided with a longitudinal rib extending from its base to its tip and each set provided with an annular rib extending around the base thereof. The various sets of teeth are arranged in a network of ribs which extend at right angles to each other, and extend from hole to hole to thereby provide a strengthened plate which is rigid and prevents bending of the plate.

distortion on being punched out.

These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended illustrations in which,

FIG. 1 is a plan view of a gusset according to the invention used for holding a series of structural members together and illustrating the method is which such a gusset plate is used;

FIG. 2 is a top plan view of a gusset plate according to the invention;

FIG. 3 is an enlarged detail view of one section of the plate of FIG. 2 taken along section lines 33;

FIG. 4 illustrates a schematic showing of the angular arrangement of rows of teeth in a plate in relation to one another;

FIG. 5 shows a detail of the rotation of the teeth in the plate whereby the teeth of one set face different angles than the teeth of the neighboring set; and

FIG. 6 is a detail of another set of teeth at a dilierent angle than the teeth of that of FIG. 5.

The plate shown in FIG. 2 includes a metal planar body 10 from which is punched a series of holes providing a plurality of teeth from each hole. The punched out teeth are arranged in sets and, as shown, the teeth include the punch- outs 12 and 14 arranged alternately from one side to the other side of the plate. Around each punched-out hole is an embossed or stamped, raised annular rib 20. Interconnecting each of the ribs are horizontal raised or embossed lines 16 and vertical embossed lines 18. The embossed straight and annular ribs provide additional strength, and in particular the annular rib provides strength around the base of the teeth in the area of A plurality of nail holes 22 are provided throughout the system between four holes and generally in the intersection of the ribs. The nail holes provide means for securing nails into the wooden structural member on which the device is placed.

Each tool hole has four triangular teeth 30 puncied from each individual hole, shown in cross section in FIG.

3. Each tooth is embossed with a rib 32- iIshown in plan in FIGS. 5 and 6) which extends from the tip 34 of the tooth to its base 36 adjacent and connected to the rib 20 leaving side areas in the plane of the original flat teeth.

Using ZO-gauge model steel with a plate of the character described, a series of holes are punched through the plate with all teeth extending from one side of the plate. With such a plate the diameter of the opening d, shown in FIG. 3, may be about of an inch and the four teeth are of a nominal %2 Of an inch long. The cutting of the teeth from the plate and forming the annular rib 20 slightly elongates the teeth so that they are somewhat longer than the diameter of the opening. It is noted that the position of rib 20 produces a slightly sloping entrance 21 to the teeth adding strength to each tooth along with the embossed rib 32 on the tooth.

Each of the openings is provided with four teeth, and the four teeth are formed in pairs opposed to each other on opposite sides of the hole. The teeth are rotated from hole to hole so that the teeth of adjacent rows do not enter the wood at the same angle. Thus, as shown in FIG. 4, a plate 40 illustrates the rotation of the teeth where square holes 41 are shown in one row and square holes 42 are shown in the next row with its teeth rotated slightly or with the teeth at a different angle from the holes 41. The dashed lines 43 in each of the openings illustrate the positioning of the teeth after being creased,

but for illustration of the rotation the teeth are shownfiat. It is noted that the top horizonal row has its teeth extending at the same angle, and where the next horizontal row has the teeth of openings 42 at an angle to that of the teeth of opening 41. Each vertical row is thus provided with teeth at a different angle than its neighbors. The rotation of the teeth with the ribs or creases is shown in FIGS. and 6 wherein the openings are arranged to have the teeth extended at a different angle. For example, in FIG. 5 the teeth with the points 34 are arranged at a specific angle a from a horizontal line whereas the opening with the points 34 shown in FIG. 6 are arranged at an angle 1) which is substantially larger than angle a of FIG. 5. Thus, by having adjacent holes with the various angles of the teeth in relation to a horizontal or a vertical line, the teeth will penetrate the Wood at a different angle thus reducing the chance of splitting of the Wood, and, further, provides better holding since the wood does not shrink evenly in all directions.

The gusset of the invention is used by abutting framing members together and then pressing the teeth of the plate into the framing members. One most commonly used framing member is a wooden member in the 2" x 4" and 2 x 6" range. As shown in FIG. 1, a series of framing members 50, 51, 52, 53, 54 and 55 are arranged in a core form for a panel. The member 50 is at right angles to member 51 and about 45 to member 52. The teeth of gusset plate are pressed into the wood about the joint of the three members, and the plate may be secured in position by means of nails. It is normally better to have at least one nail in each framing member. The members are joined together at the center where the bracing members 52, 53, 54 and 55 are abutting in the center portion, and the teeth of the plate 10 are pressed into the wood fibers of the abutting members holding the same in framing position. Here again nails are inserted through one or more of the openings and at least one nail is put into each framing member. Only a corner of the framing member is shown which is believed sufficient to illustrate the use of the gusset in joining members of a panel. All four corners are, of course, secured together by means of similar gusset plates.

The gusset plates may be made of any desired shape, square and rectangular shapes being shown. It is obvious, however, that gusset plates may be made triangular or any polygonal shape to fit the joint of the wooden member of the particular structure. It is preferable that a framing member such as shown in FIG. 1 be made of one type of lumber with uniform shrinkage. Normally a jig is provided to hold the members in position until the plates are nailed to the various joints between the members. Once the plates are secured, they may then be pressed into the wood by means of a power press having a planar surface at least as large as the gusset plate. In many instances it is desirable to put plates on both sides of the frame, in which case a plate may be placed on one side of each joint, the frame turned over, and a plate placed on the other side of each joint and then both plates pressed into the wood by means of a single press. Framing members made with such gusset plates are strong and capable of rough handling in transportation.

The gusset plates have been tested under various conditions for strength of joints made with them, and for one particular type of test the gusset plates were joined on both sides of end-wise abutting 2 x 6s. A hydraulic test machine was used to pull the two pieces of 2 x 6 apart for measuring the strength of the gusset under tension. The plates used in the testing were 3 /2 X 6 inch plates containing about 19.5 square inches and each with 30 tooth holes providing the four inch teeth per hole. Each plate was secured to the boards by means of four nails, two in each board. A series of tests on various types of wood were conducted which included pine, western hemlockconstruction grade, inland Douglas fir, and W. C. Douglas fir, taking the test samples to failure. The average force to produce failure was 9161 lbs., which is an average of 469.8 pounds per square inch of plate at failure. Applying a factor of 3 for safety, gave an average safe load of 156.6 p.s.i. of plate. Since there were thirty openings in each plate, thirty plugs of wood were cut when the plate was pressed into the wood. Based on the plugs, the average failure occurred at 305 lbs. per plug and, on the basis of a safety factor of 3, 101 lbs. per plug is the maximum loading.

Taking as a criterion a 0.015 inch slip between the two wooden members, it was found that a plate loading using the wood specified above the slip occurred at an average of 5020 lbs., which is an average plate loading of 257 p.s.i. On the basis of thirty plugs, this amounts to 167 lbs. per plug, and with a safety factor of 1.6, it amounts to 104.6 lbs. allowable per plug.

In another series of tests using yellow pine, the average tensile load at 0.015 inch deformation was 5857 lbs. and 9470 lbs. at failure. This gave a load at 0.15 inch and 1.6 safety factor of 122 lbs. per plug and at a safety factor of 3 of 105 lbs. per plug. The load per flat plate area with a safety factor of 1.6 was 187 p.s.i., and 162 p.s.i. with a safety factor of 3.

During the tests shown above there were two types of failure, one in which the plate sheared apart and another where the plate pulled from the wood.

From the above results it is easily seen that the strength of a steel plate is only 50% higher than a similar plate punched-out teeth, and considerably stronger than gusset plates heretofore used for such purposes.

I claim:

In a gusset for joining wooden members formed from a thin, integral metal body having a plurality of openings distributed over the area of the surface and four generally flat triangular-shaped teeth punched out of each opening, each of said teeth extending substantially perpendicular to said body and having a penetrating tip at its free end, the improvement of fixing said openings in rows wherein the openings in adjacent rows are staggered and the teeth in adjacent rows extend from the body at relatively different angles, a central embossed generally V-shaped rib formed in each said tooth extending from its tip to its base leaving side areas in the original plane of the tooth, with the concave side of the rib being on the inner side of each tooth, an annular embossed rib extending around each said opening and genof ribs between the openings in each row, said body having a plurality of small openings for receiving nails or the like.

References Cited by the Examiner UNITED STATES PATENTS 1,196,374 12/1915 Mader s5 49 1,671,895 5/1927 Fritz s5 49 1,647,934 11/1927 Sallop s5 11 2,142,167 1/1939 Zalkind s5 11 3,031,727 5/1962 Nesbitt s5 11 3,052,149 9/1962 West s5 13 3,090,088 5/1963 Foley s5 -13 3,104,429 9/1963 Sandford 13 CARL W. TOMLIN, Primary Examiner.

EDWARD C. ALLEN, Examiner.

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