Truss ridge-joint connector assembly

A ridge-joint connector assembly for trusses having a top chord which consists of a pair of juxtaposed parallel wood lumber members and metal web members. The assembly connects the abutting ends of the pitched lumber members and the metal chord members. The assembly consists of two pairs of metal fastener plates, a pair of ridge end-butt inserts and an elongated metal load transfer member.

BACKGROUND OF THE INVENTION 
Composite trusses constructed from metal webs and lumber top chords came 
into commercial usage about 17 years ago. About 20 percent of such 
composite strusses are pitched structural trusses and require some means 
for connecting the top chords at the ridge butt-joint. An example of such 
a composite truss and a ridge connector therefor is shown in A. L. 
Troutner U.S. Pat. No. 3,535,845 granted Oct. 27, 1970. The compression 
forces in the top chord at the ridge joint can reach exceedingly high 
numbers and the connector as constructed according to Troutner U.S. Pat. 
No. 3,535,845 imposed such high shear loads on the ridge pin that an 
especially large pin had to be used. Two years later, Troutner introduced 
another heavy duty ridge connector set forth in his U.S. Pat. No. 
3,646,725 which solved the pin shear problem but the heavy cast metal 
product is expensive and requires careful fitting of the shortened lumber 
top chords to the device and still requires two pin connections adjacent 
the ridge joint. 
On Sept. 20, 1974, Applicant filed application Ser. No. 507,943 for a new 
connector for a composite truss and this application will issue as U.S. 
Pat. No. 3,946,532 on Mar. 30, 1976. This patent relates to flat trusses 
and does not teach a connector for joining the butt ends of the pitched 
top chords. 
SUMMARY OF THE INVENTION 
The gist of the present invention is the use of prong plates with drawn 
hole openings and a ridge butt-insert plate in combination with a load 
transfer member which will provide a ridge joint assembly with low cost 
elements, some of which are similar or identical in construction to the 
elements in the other joint assemblies of the truss described in my 
previous U.S. Pat. No. 3,946,532. 
A principal object is to provide a ridge joint which produces the maximum 
load value with the least and simplest metal elements. 
An object of the present invention is to provide a ridge joint assembly 
which eliminates the need for special cast connectors and uses similar 
assembly technology and uses some similar elements as are used in the 
other joints of trusses constructed in accordance with the teachings of my 
U.S. Pat. No. 3,946,532. 
A further object is to provide a ridge joint assembly which permits the 
ends of the lumber top chords to abutt one another; separated only by a 
thin sheet metal member. 
Another object is to provide a ridge joint assembly which requires the 
removal of a minimal amount of wood from the top chord. 
Still another object is to provide a connector which can be used for both 2 
.times. 4 and 2 .times. 6 wood chords. 
A further object is to provide a connector which distributes the 
compression load of the top chord members over both the butt ends as well 
as the side faces of the wood chord members. 
Another object is to provide a connector in which the pin is so placed that 
it prevents the wood chords from shifting vertically in respect to each 
other and the pin shear occurs across the longitudinal cross section 
rather than across the transverse cross section as in all other ridge 
joint connectors.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A ridge-joint connector assembly for connecting the ends 1, 2, 3 and 4 of 
abutting top chords 6, 7, 8 and 9 and transferring tension and compression 
loads between the chord members and metal web members 11 and 12 in a truss 
structure wherein the top chords consist of two juxtaposed pitched and 
parallel lumber members, and the metal web members have flattened end 
areas 13a and 13b interposed between the lumber members consisting briefly 
of the following: two pairs of continuous sheet metal fastener plates 14a, 
14b, 14c and 14d positioned on the inside faces 16a and 16b and 17a and 
17b and outside faces 18a and 18b and 19a and 19b of the ends of the 
lumber members and each plate includes an opening 21a, 21b, 21c and 21d 
therethrough and fastener areas 22a, 22b, 22c, 22d and 23a, 23b, 23c, and 
23d on both sides of the opening and disposed from the opening leaving an 
area 24a, 24b, 24c and 24d around the opening free of fasteners; a 
plurality of sharp pointed fastener means 26a, 26b, 26c and 26d sufficient 
in number to transfer substantially all of the web load to the lumber 
members and having a length less than the width of the lumber member and 
connecting the fastener area of the plates to the chord by penetrating the 
inside and outside faces of the lumber members at a plurality of closely 
spaced intervals in order to reduce the possibility of failure of the 
lumber by splitting; the flattened ends of the metal web members are 
formed with openings 29a and 29b therethrough; each of the openings in the 
plates is surrounded by integrally formed drawn sidewalls 31a, 31b, 31c 
and 31d extending into the lumber members forming coaxial annular flanges 
32a, 32b, 32c and 32d providing bearing area; there being enlarged counter 
sunk openings 33a, 33b, 33c and 33d and 34a, 34b, 34c, and 34d in the 
inside and outside faces of the lumber members dimensioned to receive the 
annular flanges of the plates in a force fit; a cylindrical elongated 
metal load transfer member 35 having a diameter and a length dimensioned 
to transfer loads between the metal fastener plates and the metal web 
members by bearing against a substantial portion of the metal plate 
flanges in a force fit, and against the edges of the openings in the metal 
web members; the abutting end faces 36, 37, 38 and 39 of the lumber 
members are formed with hemispherical grooves 41a, 41b, 42a and 42b for 
receiving the load transfer member; means providing lateral support for 
holding the members of the assembly together; a pair of ridge-end metal 
butt-inserts 43a and 43b each covering a substantial portion of the end of 
one of the abutting lumber members and spaced therebetween, and the 
butt-inserts have hemispherical offsets 44a and 44b formed therein 
dimensioned for receipt in the hemispherical groove in one of the abutting 
lumber members; and the web members, plates, fastener means and load 
transfer member are positioned so that substantially all load transference 
from said web members to the wood chord members occurs at the interface of 
the plates and the inside and outside faces of the lumber members through 
the plurality of sharp pointed fasteners and a portion of the load is 
transferred through the offset in the butt-inserts and the load transfer 
member. 
The main loads in the ridge joint of a truss are the compression loads in 
the top chord lumber members. The end face of each 2 .times. 4 must 
withstand design loads of 10,000 pounds and the end face of each 2 .times. 
6 must withstand design loads of nearly 20,000 pounds. These loads are so 
great that simply butting the ends of the wood members together did not 
give satisfactory joint load values. Interposing metal cast fixtures 
between the shortened lumber ends such as the Troutner cast iron connector 
set forth in U.S. Pat. No. 3,646,725 was unacceptable because of the cost, 
added weight and complicated truss fabrication problems. Instead of the 
$15.00 or more Troutner connector knuckle, this application uses a light 
weight assembly costing less than $1.00. One of the elements of the 
assembly is a 20 gauge sheet metal rectangle with a 1/4 inch radius 
hemispherical bend. This ridge-butt insert is shown in FIGS. 6 and 7 and 
for the 2 .times. 4 chords, it measures a mere 13/8 inches in width and 
is 31/2 inches long. Before bending cutouts at 48 and 49 measure 3/4 
.times. 1/4 inch. The butt-insert is placed between the angle cut lumber 
ends and the hemispherical bend is inserted into the hemispherical opening 
in the end of one of each of the abutting pairs of lumber members. 
The unique feature of the present joint assembly is that all loads 
transmitted from the wood members to the metal web members are transferred 
by metal to metal contact. Part of the shear load for example, is 
transmitted from the hemispherical portion 44a of the butt-inserts to the 
bolt 35 and then directly to the openings 29a and 29b in the webs 11 and 
12. 
The primary feature of this invention is the use of fastener plates 14 
which are fully described in my U.S. Pat. No. 3,946,532. These plates have 
now been standardized at 3 inches .times. 6 inches .times. 18ga. prong 
plates. Each plate has a 1/2 inch drawn hole which accepts a No. 51/2 
inch diameter 41/4 inch machine bolt. The plates may be used with nail 
fasteners but preferably the plates are formed with prongs, struck from 
the plate leaving elongated slots. It is essential that the prong plate 
have two areas of prongs and a prong free area surrounding the opening in 
the plate. Four rows of prongs with about 11 prongs in each row has proven 
sufficient. 
As stated above, even though bolt 35 is inserted through the wood chord 
members, the bolt is almost entirely in contact with metal only so that 
loads are transferred from metal to metal. Loads, for example, are 
transferred from the sides of the wood members into the plurality of 
prongs in each plate. The load is transmitted through the plate to the 
solid prong-free portion of the plates around the openings and thence to 
the drawn flanges 32. The "hub effect" of the drawn opening in the plate 
transmits loads from the plate to the pin far in excess of the forces 
which could be transmitted by a plate with simply a hole cut in it. This 
drawn opening permits a much lighter gauge fastener plate to be used, thus 
effecting a great savings in metal weight and cost. 
plates is to be noted that 4 fastener plates are used at the ridge joint. 
Even though two fastener plaes as set forth in my U.S. Pat. No. 3,946,532 
would often be sufficient. Because of the high compression loads in the 
wood chords, it is essential that the chords remain in alignment to 
prevent any unbalancing in the truss. The fastener plates on the inside 
and outside faces of the lumber members "encapsulate" them and thus 
prevent failure at the joint. 
Another important feature of the prong plates which has been described in 
my prior patent, but is repeated herein, is the fact that they perform the 
dual function of transmitting loads while preventing splitting of the 
lumber members which is the main problem of composite wood chord/metal web 
trusses constructed in accordance with the teachings of Troutner, U.S. 
Pat. No. 3,646,725. Trusses using prong plates can use lower grades of 
lumber and less attention must be given to imperfections and knots as 
compared with the Troutner composite truss. 
Another feature of the present ridge joint is the fact that the compression 
loads are distributed evenly over the faces of the abutting lumber members 
and evenly to the inside and outside faces of the lumber members as 
contrasted with the point or pin loads experienced in the Troutner ridge 
connectors as shown in U.S. Pat. Nos. 3,646,725 and 3,535,845. With the 
joint encapsulated by prong plates, misalignment is minimized and even the 
ability to resist torsion forces at the joint under adverse loads is 
present. 
The joint is held together by placing a nut 51 on the threaded end of bolt 
35 and 12 gauge washers 52 and 53 between the head 54 of the bolt and the 
nut. 
As stated above, the use of the bolt in the hemispherical openings in the 
butt-ends of the lumber members prevents relative shifting of the abutting 
lumber members in the vertical plane. With the use of the butt-insert, 
compression of the wood fibers in the hemispherical openings due to 
crushing by the bolt is lessened by the spreading of the load by the 
hemispherical metal bend in the butt-insert. 
It should be noted that the opening in the plates could be at the mid-point 
of the plate. For ease in calculations using the same computer assumptions 
for the 2 .times. 6 and 2 .times. 4 chords, the center of the hole has 
been placed at a point 13/4 inches from the bottom edge of the plate. 
The drawings illustrate an assembly for a roof pitch 2 inches in 12 inches. 
Practical pitch may be from 0 to about 3 inches in 12 inches but with 
decreasing allowed values over 2 inches in 12 inches. In assembling the 
truss, it is essential that the chord angles at the butt joint be cut 
accurately and that the chords be tightly butted when the fastener plates 
are pressed into the lumber. 
On Dec. 26, 1975, Testing Engineers, Inc. of Oakland, Calif. tested the 
ridge joint as above described and dimensioned. For test purposes, a 1 in. 
6 pitch roof ridge truss was simulated. The compression load between 
butt-ends was imposed upon intervening ridge butt insert plates. Two 
assemblies, using chord simulators approximately 18 inches long were 
assembled as an opposed vertical pair joined together by a short length of 
1 inch diameter 14 ga. tubing with standard flattened ends, each end 
engaging 1/2 inch diameter bolts. Starret gauges were mounted at each 
joint to read to 0.001 inch compression movement across the butt joint. 
The test assembly was placed on the bed of a Baldwin Universal testing 
machine loads were placed on the assembly and the gauges read at 
increments of loading of 4000 pounds between 0 pounds and 36,000 pounds. 
Three tests were made and the minimum ultimate load was 61,500 pounds. 
Dividing by two and a safety factor of three, a minimum design ultimate 
load of 10,250 pounds was achieved. 
Referring to FIG. 1A, a modified form of the invention is shown. This form 
of the invention is exactly the same as the previously described invention 
except that the double chords are 2 .times. 6 lumber instead of 2 .times. 
4 lumber. Corresponding chords have been labeled 8' and 9'. The only other 
difference is the fact that the opening 21d' in the standard fastener 
plate 14d' is centered in the plate. This permits the opening center to be 
placed 13/4 inches above the bottom edge 56 of the intersection of the 
bottom chords so that for programming the computer the opening placement 
will be the same for the 2 .times. 4 and 2 .times. 6 chords. The fastener 
plate 14d' is the same as previously described with fastener areas 22d and 
23d and a fastener free area 24d. To accommodate the increased area of the 
ends of the 2 .times. 6 chords, the butt-insert plate 43b' is larger in 
area. The dotted area 57 shown in FIGS. 6 and 7 indicate the manner in 
which the butt-insert plate for the 2 .times. 4 chords is modified to be 
used in the chords using 2 .times. 6's. FIG. 1A shows web members 11' and 
12' which serve in the same manner in the truss as previously described. 
A test of a joint using a pair of 2 .times. 6 chords was conducted by 
Testing Engineers, Inc. on the same date and under the same testing 
procedures as previously described. An ultimate load of 118,000 pounds was 
achieved and by dividing by 2 and by a safety factor of 3 a minimum design 
load of 19,666 pounds was computed. 
The joint assemblies described for 2 .times. 4 and 2 .times. 6 chords are 
only by way of example. Lumber chords of larger or even smaller sizes are 
possible within the teaching of the invention.