U.S. patent number 3,627,362 [Application Number 04/859,230] was granted by the patent office on 1971-12-14 for spline and seat connector assemblies.
Invention is credited to John H. Brenneman.
United States Patent |
3,627,362 |
Brenneman |
December 14, 1971 |
SPLINE AND SEAT CONNECTOR ASSEMBLIES
Abstract
A continuous spline and seat connector assembly that is adapted
for use in the construction of buildings such as housing. The
spline may be inserted into a seat member in the direction of the
depth of the seat member and its removal opposed by a locking
action which occurs after the insertion of the spline.
Inventors: |
Brenneman; John H. (Princeton,
NJ) |
Family
ID: |
25330398 |
Appl.
No.: |
04/859,230 |
Filed: |
August 13, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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837495 |
Sep 1, 1959 |
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514573 |
Dec 17, 1965 |
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513652 |
Nov 26, 1965 |
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174554 |
Feb 20, 1962 |
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Current U.S.
Class: |
52/586.2;
411/460; 411/477 |
Current CPC
Class: |
F16B
5/0004 (20130101); E04B 1/6154 (20130101); F16B
5/002 (20130101); F16B 19/002 (20130101); F16B
12/10 (20130101); E04B 1/49 (20130101); E04B
1/615 (20130101); F16B 21/082 (20130101) |
Current International
Class: |
E04B
1/61 (20060101); E04B 1/49 (20060101); E04B
1/48 (20060101); F16B 5/00 (20060101); F16B
12/00 (20060101); F16B 12/10 (20060101); F16B
19/00 (20060101); F16b 005/07 () |
Field of
Search: |
;85/7,5,8.8
;287/2.92B,2.92T,2.92R ;52/584 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Allen; Edward C.
Parent Case Text
This application is a continuation-in-part of my application, Ser.
No. 514,573, filed Dec. 17, 1965, now abandoned, which is a
continuation-in-part of my application, Ser. No. 513,652, filed
Nov. 26, 1965, now abandoned, which in turn is a
continuation-in-part of my application, Ser. No. 174,554, filed
Feb. 20, 1962, now abandoned. This application is also a
continuation-in-part of my application, Ser. No. 837,495, filed
Sept. 1, 1959, now abandoned.
Claims
I claim:
1. A spline and seat connector assembly comprising:
a longitudinally extending spline member having a closed peripheral
wall and a hollow interior, said peripheral wall having two
sidewalls symmetrically disposed on opposite sides of a central
longitudinal plane, said sidewalls having outwardly facing surfaces
containing two sets of longitudinally extending, rigid, toothlike
projections on each of said sidewalls, a first set of projections
defining one end of said spline member, and a second set of
projections defining the other end of said spline member, the
locking surfaces of the projections on opposite ends of said spline
member being reversely disposed;
a longitudinally extending seat member having a longitudinal axis
lying in the same longitudinal plane as the central longitudinal
plane of the spline member comprising a pair of sidewalls on
opposite sides of said longitudinal plane and defining a spline
member receiving recess, said sidewalls having inwardly facing
surfaces provided with longitudinally extending, rigid, toothlike
projections with locking surfaces engaging the locking surfaces on
said spline member,
said seat member sidewalls being spaced apart by a distance
substantially equal to the distance between said spline member
sidewalls; and
said assembly being characterized by said spline and said seat
members having a combined sufficient resilient deflection of their
respective sidewalls to enable insertion of the spline member into
the desired locking engagement position in the seat member by
movement of said spline member relative to said seat member
parallel to said longitudinal plane in a direction normal to said
longitudinal axis without permanent deformation of either said
spline or seat members.
2. A spline and seat connector assembly as defined in claim 1
wherein said peripheral wall is in the shape of a rectangle.
3. A spline and seat connector assembly as defined in claim 2
wherein the end walls of said rectangles are arcuately shaped and
have a sufficiently thin cross section to allow the side walls to
be resiliently compressed toward each other.
4. A spline and seat connector assembly as defined in claim 1
wherein each sidewall has a group of at least three adjacent
toothlike projections and the distances across the spline member
between the outer tooth edges of the projections on opposite
sidewalls increases progressively as the distance of the tooth edge
increases from that end of the spline member.
5. A spline and seat connector assembly as defined in claim 1
wherein the peripheral wall is in the general shape of a
circle.
6. A spline and seat connector assembly as defined in claim 5
wherein the peripheral wall is generally circular but with
reentrant reverse bend portions located along said central
plane.
7. A spline and seat connector assembly as defined in claim 1
wherein said seat member contains double sidewalls, one being an
inner wall and the other being an outer body wall, separated by a
void allowing deflection of the exposed inner sidewall relative to
the body wall of the seat member in a direction parallel to said
central plane and the toothlike projections on said spline member
snapping into locking position upon insertion of said spline member
into said seat member to pull the spline joint more tightly
together.
8. A spline and seat connector assembly as defined in claim 1
wherein the seat member contains double sidewalls, an inner wall
and an outer body wall separated by a void allowing deflection of
the exposed inner sidewall relative to the body wall of the seat
member in a direction perpendicular to said central longitudinal
plane.
9. A spline and seat connector assembly as defined in claim 1
wherein the seat member is provided with an intermediate insert
between the spline member sidewall and the seat member sidewall,
said insert with directional teeth cooperating with said spline
member teeth and more sharply angled serrations cooperating with
the seat member wall in such a way as to wedge the insert against
the spline member and hold the spline more tightly upon attempted
removal of the spline.
10. A spline and seat connector assembly as defined in claim 9
wherein said insert is hinged as a flap on said seat member to
protect the seat member prior to insertion of the spline member and
to fold down into the seat member into abutting relationship
between said spline member sidewall and said seat member
sidewall.
11. A spline and seat connector assembly as defined in claim 1
wherein each of said members has a plurality of parallel toothlike
projections on each sidewall, the pitch of the toothlike
projections on one of said members is an integer multiple of the
pitch of corresponding toothlike projections on the other of said
members.
12. A spline and seat connector assembly as defined in claim 11
wherein the pitch of the toothlike projections on the spline member
is greater than the pitch of the projections on the seat member to
thereby cause a spline member to ratchet into position in said seat
member.
13. A spline and seat connector assembly as defined in claim 1
wherein the seat member has a cross-sectional configuration which
effects compression of its sidewalls against the spline member
sidewalls during said attempted withdrawal.
14. A spline and seat connector assembly comprising:
a continuous and longitudinally extending, substantially hollow
spline member having a longitudinally extending axis and a pair of
sidewalls on opposite sides of a central longitudinal plane of the
spline member passing through the longitudinal axis of said spline
member, said sidewalls having outwardly facing surfaces containing
longitudinally extending, rigid, toothlike projections thereon with
outwardly extending locking surfaces and wherein each tip of said
toothlike projections lies coincident with an imaginary line
extending substantially parallel to said longitudinal axis of said
spline member and said spline member has a length several times
greater than any of its lateral dimensions;
a longitudinally extending seat member having a longitudinal axis
lying in the same longitudinal plane as the central longitudinal
plane of the spline member, and parallel to the longitudinal axis
of said spline member and comprising a pair of sidewalls on
opposite sides of said longitudinal plane and defining a spline
member receiving recess having a length several times greater than
any of its lateral dimensions, said sidewalls having inwardly
facing surfaces provided with longitudinally extending, rigid,
toothlike projections with locking surfaces engaging the locking
surfaces of said spline member, said seat member sidewalls being
spaced apart by a distance substantially equal to the distance
between said spline member sidewalls, said seat member having an
arcuate end wall extending between said seat sidewall; and
said assembly being characterized by said spline and seat members
having a combined sufficient resilient deflection of their
respective sidewalls to enable insertion of the spline member into
the desired locking engagement position in the seat member by
movement of said spline member relative to said seat member
parallel to said longitudinal plane in a direction normal to said
longitudinal axes without permanent deformation of either said
spline or seat members.
15. A spline and seat connector assembly as defined in claim 14
wherein said spline member has an H-shaped configuration with the
upper end of the H forming one spline member and the lower end of
the H forming a second spline member.
16. A spline and seat connector assembly as defined in claim 14
wherein said spline member has an S-shaped configuration including
a central leg and crosses the joint between two opposed seat
members along each seat member sidewall and also at a third
position intermediate said sidewalls to thereby place said central
leg under compression during any attempted withdrawal.
17. A spline and seat connector assembly as defined in claim 14
wherein said spline member has a T-shaped configuration on at least
one end having a central stem parallel to said central plane and a
cross arm adjacent one end of said stem, said cross arm having free
end portions which extend over a portion of said stem and are
bendable inwardly during the insertion of said spline member into
said seat member and bendable outwardly during attempted
withdrawal.
18. A spline and seat connector assembly as defined in claim 14
wherein said peripheral wall is in the shape of a rectangle.
19. A spline and seat connector assembly as defined in claim 14
wherein the peripheral wall is in the general shape of a
circle.
20. A spline and seat connector assembly as defined in claim 14
wherein the spline member has an elongated C-shaped cross section
with opposed teeth at opposite ends of the cross-sectional
configuration to provide a double-ended spline member.
Description
This invention relates to a continuous spline and spline seat
connector assembly adapted for construction of buildings, cabinets,
and the like which will be suitable to form a strong durable
architectural joint which will satisfy mechanical strength
requirements for large structures.
Splines have been used for many years in the building trade as
tools of alignment, their most notable use being as inserts in
glued joints or in ceiling or roof panels to preclude the sagging
or uneven deflection of the structural materials used. Usually,
however, it has been considered necessary to use a device or
material other than the spline for fastening purposes. For example,
nails and/or glue are commonly used to join interior wall or
ceiling panels though, in such cases, it has usually been necessary
to leave one side of the panels unfinished so that the nailing or
gluing operation might be properly performed. In those cases where
the panels have been completely prefabricated during manufacture,
it has been necessary to use some external fastener device such as
a batten or nails to join them and to finish over any nail holes or
other exposed fasteners.
Many construction methods devised to date using prefabricated
wooden panels have necessitated substantial onsite labor for the
construction of a given unit, even where small or light buildings
are involved. In addition to the added cost in high-priced labor
areas, such methods have required the use of cumbersome and
time-consuming construction methods, such as drilling, gluing,
hammering, driving screws, etc., all of which tend to injure the
materials of construction to a greater or lesser degree and/or
require additional finishing operations.
It is a principal object of this invention to provide an improved
spline and seat connector joint assembly. In such joints the
sidewalls have a plurality of mating projections which provide a
snug, tight joint and a spline member and seat member are so
constructed as to enable assembly in a direction perpendicular to
the direction of the longitudinal axis of the slot and spline by
forming the sidewalls of one or both of the members to have
sufficient deflection without permanent deformation as to enable
the spline to be inserted in the seat and the mating projections to
engage so as to resist a force tending to remove the spline from
the seat.
Another object is to provide a variety of novel spline
configurations which are adapted for use in the connector joint
assembly of the present invention.
A still further object is to provide a variety of novel spline
receiving seat configurations which are adapted for use in the
connector joint assembly of the present invention.
These and other objects of the invention will become more fully
apparent from the claims, and from the description as it proceeds
in connection with the appended drawings wherein:
FIG. 1 is an end view of an elongated spline member formed in
accordance with the present invention;
FIG. 2 is an end view showing the spline member of FIG. 1 inserted
in an upper seat member which may be a slotted block of wood and
showing a second seat member similar to the other seat member
adapted for insertion on the exposed end of the spline member;
FIG. 3 is an end view of a spline seat that has been extruded from
a material such as aluminum or plastic;
FIG. 4 is an end view of a further embodiment of a spline member
incorporating certain principles of the present invention;
FIGS. 5 through 9 are end views of other spline members which
incorporate various principles of the present invention;
FIG. 10 is an end view of a spline member similar to the spline
illustrated in FIG. 5 but inserted in two seat members that are
held in abutting relationship by the spline;
FIGS. 11 through 14 are pictorial views of different spline members
having varying types of toothlike projecting surfaces in accordance
with the present invention;
FIGS. 15 and 16 are diagrammatic illustrations of the action of the
seat wall and spline wall during insertion and attempted withdrawal
respectively;
FIG. 17 is a transverse sectional view of a novel flexible seat
member that is adapted to be inserted in a longitudinal slot along
a post, beam or edge of a panel, or to be cast into a material such
as concrete;
FIG. 18 is an enlarged view of the spline seat of FIG. 16 in a
wooden structural member showing the spline member in position;
FIG. 19 contains four diagrams illustrating the action between
teeth 136 on the sidewalls of the seat member and teeth 142 on the
lower side of flaps 138 on the seat member of FIG. 17;
FIG. 20 is a transverse sectional view of a further embodiment of a
flexible seat member constructed in accordance with the present
invention;
FIG. 21 is a transverse sectional view of a still further
embodiment of a flexible seat member constructed in accordance with
the present invention;
FIGS. 22 is a view, to an enlarged scale, of a portion of the novel
seat member illustrated in FIG. 21, showing the manner in which the
seat member sidewall deflects when the spline member is pushed into
the spline seat;
FIG. 23 is a view similar to FIG. 22 and shows the manner in which
the spline-engaging sidewalls of the seat member deflect when a
force tends to pull the spline member from the seat member; and
FIG. 24 is a transverse sectional view showing a spline member
engaging a pair of seat members each similar to the seat
illustrated in FIGS. 21 through 23.
The basic spline connector of this invention is illustrated in FIG.
1 and in a preferred form may consist of an elongated member 20
having a generally rectangular cross section with end walls 22,
sidewalls 24 and a hollow interior. Such a spline member can be
extruded from aluminum or other suitable material and cut into
pieces having lengths that are, for example, 8-feet long when used
in connection with the erection of walls that are 8-feet high. A
plurality of outwardly extending, tooth like projections 30 are
provided on the outer surfaces of walls 24 which have a generally
inclined leading surface 32 and a trailing surface 34 which is
disposed at an acute angle with the surface 32. The intersection of
leading edges 32 and trailing surfaces 34 may form biting edges on
sidewall exterior surfaces 24. The upper and lower halves of the
spline element as shown in FIG. 1 may be identical and dimensions
in inches of a typical spline element are as follows: A=0.600;
B=0.655; C=0.660; D=0.663; E=0.666; F=0.080; G=0.150; and H=0.68.
The distance between the inside surfaces of sidewalls 24 may be
approximately one-half inch and the wall thickness of the arcuate
end walls 22 approximately 0.06 inches.
Referring now to FIG. 2, the spline member 20 is shown already
driven into a slot in a wooden seat member 36, such as a 2-by-4
that has a length perpendicular to the plane of the drawing, and a
second seat member 38 is illustrated in position to be driven onto
the exposed lower half of spline member 20 so that when assembled,
surfaces 40 and 42 of seat members 36 and 38 will be in abutting
relationship. Slot 44 in seat member 38 has parallel sidewalls 46
which may be formed by a saw cut or dado blade in wood or other
sawable material. The slot width should be slightly less than the
0.6 nominal width of the spline member 20, the exact amount
depending somewhat on the relative compressibility of the wood
fibers.
Where spline member 20 is made of a hard material like aluminum,
the spline may be driven as by hammer blows into the slot of seat
member 36. Alternatively, a board may be forced against the spline
member with one or more blows to more uniformly distribute the
insertion force against face 48 of spline 20 to avoid deforming the
edge of the spline. During such insertion, the walls 46 of the slot
in the seat member are urged apart and the walls of spline member
20 having the toothed projections are compressed inwardly, but
without permanent deformation of either the spline or seat member.
Thereafter, a force tending to remove spline member 20 from the
slot causes the projections on the spline to bite into and in
effect, form mating projecting surfaces on sidewalls 46 of the slot
in the seat member. Where sufficient force to remove spline member
20 against the holding power of the teeth has been applied, the
seat member has been found to fracture along grain lines of the
wood. Thus, when two seat members 36 and 38 are secured together in
abutting relationship by spline member 20, a firm joint is provided
which will not fail under normal loads. Because the seat member is
normally 4 inches or so, resistance against tilting of one seat
member relative to the other is provided.
To assemble seat member 38 over the exposed end of spline 20 after
it has been inserted in seat member 36, difficulty is sometimes
encountered particularly if seat member 38 is an edge frame on a
4-by-8-foot panel. In such case, the impact force for insertion
must be applied at least 4 feet from spline member 20, and the
force impacts may be attenuated by the panel so much as to prevent
assembly. In such case, a saw cut 50 (see FIG. 2) running
longitudinally of the spline has provided increased resilience and
flexibility in the spline member so as to enable seat member 38 to
be placed in position. Since the teeth are shaped to lockingly
engage the side wall surfaces 46 of slot 44 in seat member 38,
sufficient holding force is provided even though the spline member
has been cut by slot 50.
In a building system it is also desirable to use structural frames
made of materials other than wood. Panels can be formed with four
edge frame members serving as the perimeter, and panels attached
into place on either side to form a wall. For the edge frames, I
have found certain configurations can work effectively as seat
members for the splines of this invention.
Referring now to FIG. 3, a seat member 52 adapted to receive
one-half of the spline member 20 of FIG. 1 is illustrated which may
be used as an edge frame member for a beam, post or panel. Seat
member 52 may be formed by extruding from a suitable material such
as aluminum, and be provided essentially with spaced sidewalls 54
and 56 that are capable of a slight separation. In the illustrated
embodiment, seat sidewalls 54 and 56 are joined by an end section
58 which is U-shaped and dimensioned so as to provide a resilient,
flexible lateral displacement of sidewalls 54 and 56 without
permanent deformation. End extensions 60 and 62 on opposite sides
of the seat member may be of any suitable size or shape as may be
determined by the requirements of the beam, post or panel.
If the seat member is formed of a material such as aluminum or a
hard plastic building material, or if the spline member is formed
of a synthetic plastic material or other comparatively soft
material, the toothlike projections on spline member 20 will not
lockingly engage the slot wall surfaces if smooth wall surfaces are
provided. Therefore, in such cases, the seat member sidewalls
should have surfaces which can lockingly engage with the toothlike
projections on spline member 20. For this reason, the seat member
of FIG. 3 is provided with toothlike projections 64 which may have
a shape similar to the corresponding projections 30 on spline
member 20. The spacing of projections 64 must, of course, be such
as to lockingly engage with projections 30 of spline member 20 and
for the dimensions, M=0.62 and N=0.676 are representative values
that are satisfactory where the thickness of arcuate section 58 is
about 0.06 inches.
To provide a satisfactory spline and seat connector joint of the
type described, it is important to have configurations that allow
separation of the seat slot sidewalls and/or compression of the
spline sidewalls all the way to the location where the leading
portion of the spline seats into the seat member. Mere cantilever
bending of the seat member about a hinge as at 66 of FIG. 3 would
allow displacement of the mouth or upper end of the seat member
slot, but would not allow the upper slot teeth to engage the
corresponding spline teeth near the center portion of the spline
when the spline is inserted completely into the slot.
Unsatisfactory spline and seat member configurations result in
permanent deformation such as galling of the toothlike projections,
bending beyond the yield point or fracture of one or more parts.
Prior art spline and seat fasteners such as shown in Canadian Pat.
No. 549,089 and Belgian Pat. No. 531,202 which superficially appear
similar to the spline and seat connector assembly of the present
invention are not satisfactory because of defects resulting from
the absence of flexibility and resilience necessary to prevent
permanent deformation.
Referring now to FIGS. 4 through 10, various configurations are
illustrated which may be used as the cross section for the spline
member in accordance with the principles of the present invention.
In each of these embodiments, the spline has been rotated
90.degree. from that illustrated in FIGS. 1 through 3 so that the
direction of insertion is horizontal rather than vertical. In FIG.
4, the cross section resembles an H rather than a rectangle as in
the embodiment shown in FIG. 1. The sidewalls at each end of the
fastener contain the two finlike projections that are rigid and not
easily deformed. The number of teeth illustrated in each sidewall
is two; it should however be recognized that in some instances one
tooth might be needed whereas other applications may require four
or more teeth.
One advantage of the embodiment illustrated in FIG. 4 is that the
sidewalls are more easily deflected toward each other than in the
embodiment illustrated in FIG. 1. The sidewalls on both ends of the
spline member are formed to deflect toward a central plane
indicated by center line 68. It can be observed that the central
plane 68 of the spline when it is located in a seat member
coincides with the central plane of the seat member.
The spline embodiment in FIG. 5 is in the form of an S. The opposed
teeth on sidewalls 70 and 72 can deflect toward each other upon
insertion of the spline in a seat member. Similar deflection is
provided for the teeth on side walls 74 and 76. The opposite end
sections of the spline are joined together by a reverse curved
portion 78 whose rigidity can be controlled by variation of its
thickness. When subjected to a withdrawal force, the reverse curved
portion 78 urges the spline walls outwardly against the seat
sidewalls.
The spline element illustrated in FIG. 6 has a generally circular
cross section with the opposed teeth on sidewalls 80 and 82 lying
in arcuate paths. The teeth for the other end of the spline formed
on sidewalls 84 and 86 lie in a similar arcuate path. As the spline
is inserted in a seat member, the sidewalls will move in the
direction of the arrows to thereby conform with the shape of the
sidewalls of the seat member which may have a disposition other
than parallel as will be discussed below.
In FIG. 7, a further embodiment is illustrated wherein the
sidewalls 88 and 90 are joined by a central section 92 and
corresponding sidewalls 94 and 96 are free end portions capable of
deflecting in the direction of the arrows toward the other sidewall
portions. In this embodiment, the toothlike projections are not in
alignment since it is not essential in all applications that the
two sidewall portions 90 and 96 for example be symmetrical.
FIG. 8 shows a further embodiment wherein the sidewalls containing
the teeth are capable of deflection in the direction of the arrows
as illustrated. The central section 98 is here shown as a flat
plate; it should, however, be recognized that it may be formed with
appendages such as a central stiffening ridge (not shown) running
the length of the spline on one or both sides.
FIG. 9 illustrates an embodiment similar to that of FIG. 8 but
having a T-shaped connector on each end. The connector on the left
end portion 100 is illustrated to have three teeth on each sidewall
whereas the connector on the right end portion does not have teeth
on the sidewall surfaces 103, but instead relies on the end
surfaces 104 for engaging a tooth in a seat member to lock the
spline in position. FIG. 9 is also illustrative of a spline where
the opposite ends are not identical.
FIG. 10 shows a further embodiment of a spline 105 which has a
configuration similar to that of FIG. 5 inserted in a pair of seat
members 106 and 107. Spline member 105 may be a sheet of steel or
other resilient material which can be formed as by rolling to have
an S-shaped configuration. The only locking surfaces on the spline
are at its opposite ends 108. The seat comprises a rectangular or
U-shaped slot with locking surfaces or laterally offset grooves 109
that may be formed on both sidewalls of the seat member so the
spline can be inserted in either direction. The spline member 105
is formed with sidewalls 110 which each bridge across the gap
between the seat sidewalls in seat members 106 and 107. This
particular embodiment of the spline member can be very
inexpensively manufactured and would be satisfactory for many
applications.
Referring now to FIGS. 11 through 14, there are here illustrated
four spline members each having different types of toothlike
projections which may be used in accordance with the present
invention. In FIG. 11, the toothlike projections on the sidewalls
comprise longitudinally oriented rows of parallel teeth 111 all of
whose leading faces 112 slope upwardly toward the longitudinal
center of the sidewalls. Trailing faces 113 of each of the
toothlike projections form an acute angle with the leading faces
108 to provide a relatively sharp biting edge 114 on each of the
teeth.
Thus, as can be clearly seen in FIG. 11, the sidewalls may be
longitudinally divided into two substantially equal portions 115
and 116 which each have two sets of projections that are mirror
images of each other. While the spline members may be readily
formed of aluminum, it should be understood, however, that other
materials such as plastic may be used especially in embodiments
where the spline receiving seat slots have sidewalls with preformed
interengaging surfaces such as shown in FIG. 3. Where, however, the
seat member is wood as shown in FIG. 2, it is necessary that the
toothlike projections be made of a hard material such as metal,
although the balance of the spline may be made of another material
or a similar material but having different degrees of hardness.
In the embodiment illustrated in FIG. 12, the toothlike projections
have concave or hollow ground, intermittent teeth in which
alternating notches gouged in the teeth provide sharper punching
power for use with wooden seat members as shown in FIG. 2 where the
wood has pronounced hard and soft annual rings, such as in Douglas
Fir.
FIG. 13 shows a spline member having a series of rows of
intermittent, burrlike teeth having outstanding punching ability
with respect to tough or variable hardness wood and plastic
structural units. Such a section may be extruded with flat sides
and the teeth may thereafter be cut in a separate operation by
means of a gougelike cutter adapted to raise extremely sharp edged
burrs.
The spline member shown in FIG. 14 is provided with continuous,
straight beveled teeth. This tooth configuration is similar to that
illustrated in FIG. 11 except that its toothlike projections are
more closely spaced than those in FIG. 11 and have a flat rather
than concave or hollow ground leading faces. As in the case of the
spline element of FIG. 11, this spline configuration is generally
universally adaptable to various requirements, and because of its
closely spaced, biting surfaces, it can ratchet into a seat having
preformed teeth with double or triple the spacing as illustrated in
FIG. 3.
Referring now to FIG. 15, and also to FIGS. 1 and 3, a fragmentary
view of one side of the spline and one side of the seat illustrates
the sidewall action in those embodiments of this invention where
the sidewall of both the spline and the seat member have preformed
teeth. The insertion of force F on the spline causes sloping
surfaces to engage as illustrated in FIG. 15 and produce opposed
forces tending to separate the seat sidewalls and to compress the
spline sidewalls. The teeth must be sufficiently rigid to avoid
permanent deformation as by crushing during insertion.
FIG. 16 illustrates the action resulting when a force is applied
tending to remove the spline after it has been inserted in the seat
member and the interlocking surfaces 120 on the spline have engaged
the corresponding surfaces 122 of the seat.
If surfaces 120 and 122 are at right angles relative to the
direction of insertion and removal, fracture of the teeth will be
required for removal unless the teeth slide apart as during
insertion. However, if the slope of surfaces 120 and 122 is
slightly more than 90.degree. as illustrated in FIGS. 14 and 15,
then a force tending to cause withdrawal can produce force
components tending to compress the seat sidewalls together and also
to separate the spline sidewalls. This action tends to increase the
area of locking engagement between surfaces 120 on the spline and
122 on the seat, thereby producing a joint of even greater holding
power, and of course, eliminating the possibility of the teeth
sliding apart. On the other hand, the locking surfaces 120 and 122
of the teeth may be sloped to allow removal of the spline from the
seat member with a predetermined pulling force to facilitate
assemblies which are intended to be taken apart and
reassembled.
For representative dimensions as given in connection with the
spline of FIG. 1 where the width is approximately 600 mils and the
tooth depth is approximately 30 mils with a reasonable tolerance
from the extrusion die which may be .+-. 10 mils, the tooth
dimensions are limited by the strength of the material from which
the spline and seat member sides are formed, against crushing if
the sharp ends of the teeth are to be reasonably protected against
bending over or galling. Also important is the force required to
separate the seat walls and/or compress the spline walls by a
distance of 30 or 40 mils necessary to permit assembly of the
spline in the seat. Since in some applications the spline element
must be comparatively strong and hence its sidewalls cannot be made
to provide the requisite displacement, it becomes desirable to
provide seat members with walls which can separate sufficiently far
to permit the use of such comparatively rigid spline members
without sacrificing the strength or other requisite properties of
the spline and seat connector assembly joint.
Other embodiments of the seat member of this invention which may be
used with the spline members described, and which have particular
utility with the splines having the more rigid structural
configurations are shown in FIGS. 17 through 25. In FIG. 17, a seat
member 130 is separately illustrated which may be used as an insert
in a structural member as illustrated in FIG. 18. Seat member 130
of FIG. 17 has a substantially rigid end wall 132 and sidewalls 134
which are extruded or other wise formed from a thick plastic such
as the polyformaldehyde resin produced by E. I. Dupont and Co.,
under the trademark Delrin. Other suitable flexible plastic
materials are acetal resins, urethane or polyurethanes,
polyethylene, nylon, vinyl chlorides or vinyl chloride acetate.
The inner surfaces of sidewalls 134 may be provided with inwardly
projecting serrations or teeth 136 along their upper portions and
flaps 138 attached to the upper end of sidewalls 134 by means of
integral hingelike tongues 140 which initially hold flaps 138
inwardly toward the longitudinal axis centerline of seat 130. Flaps
138 are shown in their normal position in FIG. 16 (i.e., when there
is no spline connection in the seat). The flaps may advantageously,
though not necessarily, form a closure and prevent undesired
foreign material such as pieces of concrete from becoming lodged in
the seat prior to insertion of the spline member.
The lower surfaces of flaps 138 carry a plurality of teeth 142 for
cooperating with teeth 136 on the seat sidewall when flaps 138 are
forced downwardly and outwardly by insertion of a spline fastener
131 (FIG. 18) into seat 130 as will be explained. The upper
surfaces of flaps 138 are similarly provided with upwardly
extending toothlike projections 146 for cooperating with the
projections on spline fastener 131.
The lower surfaces of flaps 138 are spaced slightly from sidewalls
134 when spline fastener 131 is fully inserted in seat 130 as
illustrated in FIG. 18. This spacing enables seat flaps 138 to
separate during insertion of spline fastener 131 to provide the
desired resilience and flexibility without deformation. Upon
attempted withdrawal of spline fastener 131, the trailing surfaces
of the spline teeth lockingly engage the trailing surfaces of flap
projections 146 pulling the flaps upwardly and causing flap teeth
142 to cam against seat sidewall teeth 136 thereby moving seat
flaps 138 toward each other and tending to lock spline fastener 131
firmly in position and resisting its withdrawal from seat member
134. Seat 130 may be inserted into a slot in any suitable material
and still, through flaps 138, provide sidewalls which separate
resiliently and without permanent deformation to secure spline 131
in position.
FIG. 19 illustrates diagrammatically the configuration of the flaps
for various phases of loading. When spline fastener 131 is forced
into the seat, flaps 138 fold or bend back against sidewalls 134 to
physically engage serrations or teeth 142 on flaps 138 with a
serrations or teeth 136 on seat sidewalls 134. This provides a
desirable property of resilience and flexibility for the spline
member as it engages the sidewalls of seat member 130 during
insertion. The mating teeth 142 and 136 permit limited action
illustrated in FIG. 19 between a flap 138 and sidewall 134. When
the spline member is placed in position to cause only a "normal
load," a small space is provided between teeth 136 and 142. When
the spline is inserted, teeth 136 and 142 are compressed tightly
together. When a force is encountered which tends to expand the
joint or to pull the spline from the seat, action designated
"Expansion" occurs. When a force tending to contract the joint is
encountered, the limited action designated as "Contraction" occurs.
These comparatively small movements prevent weakening of the
holding strength of the joint and reduce the likelihood of damage
to the other components in the system.
While the foregoing discussion assumed that flaps 138 would fold or
bend when the spline is inserted, the flap may be formed originally
with a weakened cross section along a line at 140 so that a
fracture occurs and flaps 138 would thus be fractured into a
separated member. Alternatively, the seat member 132 may be
originally formed without flaps, and thereafter inserts that have
the shape of flaps 138 may be placed between one or both of the
seat sidewalls and the spline sidewalls. Such an arrangement can be
used with seat members and spline members which both are so rigid
and inflexible as to not work satisfactorily since the lateral
deflection and locking action are in significant part provided by
flaps 138.
FIG. 20 illustrates a flexible seat member which is especially
adapted for use with wooden structural components or with
components having a wooden edge frame combined with other
structural materials. An inwardly directed hat-shaped slot 150 is
cut in the wooden component or edge frame member 152 to receive a
seat member 154 which may be made of any of the suitable plastic
materials noted above in conjunction with the flexible seat member
illustrated in FIGS. 17-19 or of a metal such as aluminum or steel,
for example, having sufficient elasticity.
Seat member 154 is provided with sidewalls 156 having smooth outer
surfaces at front flange portions 158 that are used to secure seat
member 154 to the frame member as with an adhesive (not shown) or
screw fasteners 160, for example. The inner surfaces of the
sidewalls 156 may be provided with one or more teeth 162 which are
adapted to engage spline member teeth and the sidewalls 156 are
formed to have resilience to permit the spline member to be driven
into its locking position by a sidewall construction that includes
voids 168. The size of the voids in the wall between teeth 152 and
void 154 are selected by taking into consideration the properties
of the materials used to provide the requisite resilience. As
previously discussed, the use of a larger number of smaller teeth
on the sidewalls of the seat member 154 than the spline connector
has, offers the advantage of the ratchet locking action and can
decrease the requirements of the magnitude of deflection necessary
for assembly and yet provide adequate strength for many
applications.
A further embodiment of a flexible seat member in accord with the
present invention is illustrated in FIG. 21. The seat member is
here illustrated as an edge frame in a panel, post or beam 170 that
has veneer surfaces 172 and 174 on opposite sides and a serpentine
layer 176 serving as a gasket on both sides of the spline seat.
The spline seat sidewalls 178 and 180 are formed with spline
engaging teeth 182 and are supported from the seat element 184
which has two sidewalls 186 and 188 secured to the structural
element 170, by connecting links 190 and 192. The end portions of
connecting links 190 and the adjoining end portions of the seat
sidewalls 178 and 180 are tapered to a reduced cross section so
that the intersections of the connecting links with the seat
sidewall will have relative pivotal movement to thereby act as a
hinge at point "a." A similar construction provides a hinge at
point "b." The rear or inner edges of seat sidewalls 178 and 180
are joined to seat member 184 by an L-shaped link 192 having legs
194 and 196. The links are so formed as to provide a hinge action
at points "c" and "d." The above-described members are arranged
substantially in the form of a parallelogram with the fixed seat
sidewall and the spline-engaging sidewall forming one pair of
substantially parallel walls and the end links 190 and 192
providing the other pair of walls, albeit not precisely parallel.
While the points "a" through "d" are shown in FIG. 21 only on for
sidewall 180, the construction is advantageously symmetric and is
the same for sidewall 178.
The spline-engaging sidewalls 178 and 180 may be bowed toward the
center of the seat member recess and have formed thereon a large
number of small teeth 182, as illustrated, for engaging the
toothlike projections on the spline connector. The spacing of the
teeth as illustrated in FIG. 24 is such that there are exact
integer multiples of teeth 182 for every spline tooth.
Referring next also to FIG. 22, when the spline member is forced
into the slotlike recess of the seat member, the action is such
that spline-engaging walls 178 and 180 are forced apart, which is
upwardly as viewed in FIG. 22, by the toothlike projections on the
spline acting against teeth 182 on sidewalls 178 and 180. Because
of the angles between sidewalls 178 and 180 and the connecting
links 190 and 192 by which they are connected to the fixed portion
of the seat member 184, sidewalls 178 and 180 deflect apart and
toward the left in the direction of arrows A from the dotted-line
position to the position shown in full lines as shown in FIG. 22.
When the spline is forced further toward wall 184, sidewall 180
will move between the two positions shown in FIG. 21 as teeth 182
slide across the spline teeth. By using a larger number of smaller
teeth 182 on the sidewall 180 than is used on the spline member as
illustrated in FIG. 24, a ratchet action is achieved and the
displacement between the two positions shown in FIG. 22 is reduced.
For this purpose, the same result may be achieved by having the
larger number of smaller teeth on the spline rather than on the
spline seat as illustrated.
When the spline is fully inserted, the sidewalls 178 and 180, due
to their inherent resiliency, snap back against the spline with
teeth 182 on the seat sidewalls 178 and 180 engaging the toothlike
projections on the spline, thereby pulling the spline further
forward into the spline receiving recess of the seat member thereby
insuring a snug, tight joint. At the end of this "snap back"
movement, the locking members will be in the position shown in
FIGS. 22 and 24.
Referring now to FIG. 23, action is illustrated for the situation
where a force is applied for removing the spline from its seat
member. When a separating force is applied, legs 194 and 196 of
link 192 are placed in tension thereby swinging away from their
dotted-line position next to the fixed portion of the seat member,
allowing sidewalls 178 and 180 to move toward each other in the
direction of arrow B in FIG. 23 and thereby forcing the lower
section 181 of side 180 inwardly toward the center of the seat
member recess and, therefore, more tightly against the spline.
During this sequence, links 190 pivot in the direction of arrow A
pulling the upper sections of sidewalls 178 and 180 away from the
spline. However, at the same time, the sidewalls 178 and 180 are
distorted from the substantially straight configuration of FIG. 22
to their normal inwardly convex shape (see also FIG. 21), thereby
maintaining a tight gripping contact between the lower sections of
sidewalls 178 and 180 and the spline.
FIG. 23 illustrates in section a spline 200 as it appears when
securing two structural members 202 and 204 together, the action of
the seat members during the insertion step having been described in
connection with FIGS. 21-23. Once the assembly is completed, the
joint is permanent and cannot be disassembled normally without
damage to one or more of the parts.
The invention may be embodied in other specific forms without
departing from the spirit or essential characteristics thereof. The
present embodiments are therefore to be considered in all respects
as illustrative and not restrictive, the scope of the invention
being indicated by the appended claims rather than by the foregoing
description, and all changes which come within the meaning and
range of equivalency of the claims are therefore intended to be
embraced therein.
* * * * *