Note: Descriptions are shown in the official language in which they were submitted.
`~ i741~
CONNECTING APPARATUS
Field of_the Invention
The present invention is directed to connecting
- apparatus between structural members, such as structural
tubes~ trusses, space Erame nodes and other such structural
assemblies.
- - Background of the Invention
A truss is understood to comprise a plurality of
~~ parallel tubes, bars, rods or other straight members held
- _ spaced apart at various points along the length of each of
- the members in order to form a stronger structural member
. than each member would be individually. For fabrication or
- 15 other reasons, the trusses have lengths which are usually
shorter than a span across which they are to extend.
Consequently, it is necessary to connect trusses end to end
and, also, to connect end trusses to structural walls or
-other such items. The almost universal mechanism for making
such a connection is to bolt one truss to another or to bolt
the ~russ to a structural wall. Nut and bolt connections are
positive, and structural adequacy is easily veriied. The
disadvantage with nut and bolt connections is that they are
time consuming to accomplish and, consequently, expensive.
A ~pace ~rame commonly includes a plurality of
nodes and tubes in various arrangements depending on the
application. Space frames are used to support roofs, walk-
ways, scaffolding, and often provide modern looking struc-
tural support in architecturally pleasant buildings such as
halls, churches, office buildings, etc. More particularly, a
space frame is constructed by a single tube extending between
a pair of nodes. Each node has a plurality of faces and can
receive a tube at each face. Therefore, it is common for a
number of tubes to be attached to a single node so that a
3S complex9 but usually uniform, pattern is formed.
Representative connecting devices are shown in a
number of patents. For example, U. S. Patent 2,149,844 shows
a sleeve device into which one or more tubes may be inserted
and welded. U. S. Patent 4,343,562 shows a somewhat dif-
ferent structure but also utiliæes the concept of inserting atubular member into a core member and welding the two. -Other
patents show different concepts. For example, U. S. Patent
3,914,060 shows a node member having a plurality of studs
with sleeves attached thereto for threading onto ends of
tubular sections. U. S. Patent 4,023,913 shows a connector
having socket-like ends over which tubular members fit. U.
S. Patent 4,313,6~7 shows a node having a plurality of
threaded o~enings, each of which are for receiving a bolt
retained to an end of a tube. A pair of threaded bodies
lS attached to the bolt ~unction to tighten the tube to the
node. Other commercial systems are available which actually
have a threaded rod fixed at the end of a tùbe for threading
into a threaded openin~ in a node. Finally, still a dif-
ferent concept is shown in U. SO Patent 4,34~,318 wherein a
node connection includes a plurality of half joints having
~ semicircular tongue and groove elements with tubes having
; similar tongue and groove elements mating therewith. Locking
; latches are provided to keep the halves from separating.
Some of these various connectors are less complex
than others, and some are less expensive to make and use. In
general, however, various presently known connectors require
a significant amount of work time to complete the connection.
That is, a welder must weld, or a laborer must thread one
piece to another. U. S. Patent 4,340,318 perhaps re~uires a
lesser amoun-t o~ assembly time, but likely is fairly expen-
sive to manufacture due to the complex design of the tongue
and groove assembly and the locking latch assembly.
Thus, although numerous connecting assemblies are
known, there continues to be a need for improvements which
... . .... .
will simplify and make less expensive without decreasing
structural strength or reliability. In this regard, the
present invention advances connector art significantly.
YU~ tb~ Inv-nti~A
According to one aspect of the present invention
there is provided interconnect mechanism between first and
second structural members, said first structural member
including a first tube and said second structural member
including a second tube comprising:
a button having first and second ends;
first means for fastening said button at the first
end to said first structural member, said first
fastening means including a first solid rod
fastened in an end of said first tube and a first
bolt for fastening said button to said rod;
means for receiving said button, said receiving means
including a cradle having a wall on one side and a
lip on an opposing s;;de, said cradle being shaped
to receive relatively snugly said button between
said wall and said lip; and
second means for fastening said receiving means at
said wall to said second structural member, said
second fastening means including a second solid rod
fastened in an end of said second tube and a second
bolt for fastening said cradle to said second rod;
whereby reception of said button in said cradle
interconnects said first and second structural
members.
According to another aspect of the present invention
there is provided Connecting apparatus, comprising:
a tube having opposite first ends;
a cylindrical rod having a second end, said rod being
. j,, .~
, . 3
- 4 -
fastened in one of said first ends of said tube;
a cylindrical button a-ttached to said second end of
said rod, said button having a first diameter
greater than said rod;
means for receiving said button, said receiving means
being attached to a structural member, said
receiving means including a block having a
cylindrical wall with first and second ends, said
block having a second diameter greater than said
button, said block having a cavi~y extending
inwardly from the cylindrical wall, said cavity
having a semi-cylindrical end coaxial with said
block, said block having a slot in the first end
for receiving said rod as said caYity received said
button, said slot having a width less than the
first diameter of said button.
Preferably, the dimensions of the button match
relatively closely the dimensions of the cavity so that the
button, although loose, is snugly received in the cradle.
Such connection is then not only quite solid, but provides
structural strength which is predictable and can be used
advantageously for design purposes.
According to another aspect of the present invention
there is provided interconnect mechanism between first and
qecond truss members~ each of said truss members including a
plurality of interconnected spaced apart tubular members,
said interconnect mechanism comprising:
a plurality of buttons to include one for each
tubular member of said first truss member;
first means for fastening each of said buttons to an
end of a tubular member at an end of said first
truss member;
a plurality of means for receiving said buttons to
include one for each of said button~;
~.2~
second means for fastening each of said receiving
means to an end of a tubular member at an end of
said second truss member; and
means for locking said first and second truss members
together, thereby preventing said buttons from
sliding from said receiving means, said locking
means including means for rotating said receiving
means with respect to said tubular member to which
said receiving means is attached.
According to a further aspect of the present
invention there i9 provided interconnect mechanism between
first and second truss members, each of said truss members
including a plurality of interconnected spaced apart tubular
members, said interconnect mechanism comprising:
a plurality of buttons to include one of said buttons
for each of said tubular members of said first
truss member;
first means for fasten:ing one of said plurality of
buttons to an end of each of said tubular members
of said first truss member;
a plurality of means for receiving said buttons to
include one receiving means for each of said
buttons;
second means for astening one of said plurality of
receiving means to an end of each of said tubular
members of said second truss member, each of said
second fastening means including means for rotating
said receiving means with respect to said tubular
member to which said receiving means is fastened,
each of said second fastening means further
including means for preventing rotation of said
rotating means;
whereby said buttons fastened to said first truss
member are receivied by said receiving means
~. .
- 5a -
fastened to said second truss member and said
receiving means is rotated utilizing said rotating
means and locked with said rotation preventing
means, said rotated receiving means preventing said
first truss member from disconnecting with respect
to said second truss member.
A ~pring bias plunger or some other means of
preventing rotation may be used to hold the rotated receiver
from inadvertently rota~ing further. The receiver is
advantageously knurled so that it may be readily grasped and
turned preferably by hand. The plunger preferably includes a
cammed device or other similar device for retracting the
plunger from the cavity into which it falls to prevent
further rotation. ~he cam and the knurled wall on the
receiver alleviate the need for extraneous tools while
connecting the truss members together or disconnecting them.
The most advantagous alignment of rotated receivers attached
to a truss memeber occurs when the centerline of the cradles
of each of the receivers passes near the centerline of the
truss member. In this case, the only way the two truss
member could be unintentionally disconnected would be for the
truss member with attached buttons to explode outwardly,
which is unlikely.
According to a still further aspect of the present
invention there is provided a method for connecting a first
truss member to a second truss member, said first tr~ss
member having a plurality of first tubular members with
buttons attached to a first end of each of said first tubular
members, said second truss member having a plurality of
second tubular members with a button receiving means attached
to a second end of each of said second tubular members, said
button receiving means being formed in the shape of a cradle,
said second -truss member including means for rotating each of
said button receiving means, said second truss member further
~ 3~ 7~
- 5b -
including means for preventing the rotation of each of said
button receiving means, said second truss member having a
first centerline, each of said cradles having a second
centerline, said method comprising the steps of:
aligning all crad]es to open in the same direction
with the second centerlines being substantially
parall~l to one another;
moving said first truss member so that said buttons
are received in the cradles of said button
receiving means of said second truss member;
rotating said rotating means of at least one of said
button receiving means so that all of the second
centerlined of said cradles are no longer parallel
with one another; and
functioning said rotation preventing means to prevent
said rotating means from rotating any further.
The present connecting apparatus is further
advantageous for use in creating space frame struc~ures. A
node may be formed to include a plurality of faces with
receivers fastened to one or more of the faces. Tubes may
then be connected thereto in the usual fashion by placing a
button in a cradle and locking it in place. Thus, in a
fashion similar to connecting a pair of trusses together, the
creation of a space frame using the present connecting
mechanism is simple and quick, yet strong and positive.
Thus, according to a further aspect of the present
invention there is provided interconnect mechanism for a
space frame, comprising:
a plurality of tubes each having an end and a solid
rod fastened in said end;
a plurality of buttons, each of said buttons
including a cylindrical disk portion;
first means for fastening each one of said buttons to
one of said solid rods, each of said first
.~ .
- 5c -
fastening means including a first bolt attaching
said one button to said one solid rod;
a node with a plurality of faces;
a plurality of means for receiving one of said
buttons attached to one of said tubes; and
second means for fastening each one of said plurality
of receiving means to one of said faces, each of
said second fastening means including a second bolt
attaching said one receiving means to said one face
of said node.
Also according to this aspect of the present
invention there is provided interconnect mechanism for a
space frame comprising:
a tube having opposite ends and a solid rod fastened
in each said end;
a pair of buttons, each of said buttons including a
cylindrical disk portion;
first means for fastening each one of said buttons to
one of said rods, each of said first fastening
means including a first bolt attaching said one
button to said one solid rod;
a pair of nodes, each of said nodes having a
plurality of faces,
a pair of means for receiving one of said buttons,
second means for fastening each of said receiving
means to one of said faces of one of each of said
nodes, each of said second fastening means
including a second bolt attaching said one second
fastening means to said one face of said one node;
whereby said tube extends between said nodes as
~uttons are held in said pair of receiving means.
Thus, the present connecting mechanism is a
significant improvement over known conneckors, not only
because of the simple design and consequent inexpensive
- 5d -
manufacture, but also because of the ease of assembly, yet
strength of connection and capability of preventing
disconnection.
These advantages and other objects obtained by this
invention are further explained and may be better understood
by reference to the drawings and descriptive matter
hereinafter. Preferred and other embodiments of the
invention are illustrated and a detailed description is
provided.
Brief Descr~ption of the Drawin~s
FIGURE 1 is an exploded, perspective view of the
interconnecting mechanism betweeen a pair of tubes;
FIGURE 2 iS a perspective view of a pair of tubes
~a~
connected with the interconnecting mechanism of the present
;nvention;
FIGURE 3 is a cross-sectional view~ taken along line
3-3 of FIGURE 2;
FIGURE 4 is a perspective view of a porti~n of a
space frame, showing two nodes and a plurality of connecting
tubes, wherein connectors in accordance with the present
invention are used;
FI~URE 5 is a perspective view of connecting appara-
tus in accordance with the present invention for a pair of
triangular trusses;
FIGURE 6 is a perspective view, similar to FIGURE 5,
for a pair of box trusses;
FIGURE 7 is an end elevational view of an alternate
emhodiment of a receiver in accordance with the present
invention;
FIGURE 8 is a cross-sectional view taken along line
8-8 in FIGURE 7 and also showing a cross-sectional view of a
button as attached to a tubular member;
FIGURE 9 shows both a side elevation and an end ele-
vation of first and second truss members coming together for
connection; and
FIGURE 10 shows an end elevational view of two con-
nected truss members with one of the truss members in cross
section.
Detailed Description of the
Preferred Embodiment
In the drawings like reference numeral.s designate
identical or corresponding parts throughout the several
:30 views. In ].ike fashion, like numerals, only primed, are used
in description of corresponding parts ~or alternate embodi-
ments and various applications~ Referring now to FIGURE 2,
interconnectlng apparatus in accordance with the present
invention is designated generally by the numeral 10.
Apparatus 10 includes a button 12 attached to a solid rod 14
--7--
fastened within tube 16. Button 12 is contained within
receiver 18 fastened to rod 20 which is fixed to tube 22.
Retainer 24 clip prevents button 12 from undesirably sliding
out of receiver 18.
More particularly, with reference to FIGURES 1-3
button 12 is a cylindrical block having a pair of ends 26,
28. Button 12 is provided with an axial passage 30 in com-
bination with an axial cavity 32 in end 26 for receiving the
shank and head of screw or bolt 34, respectively. Cavity 32
is sufficiently sized to receive the head of screw 34 so that
it does not extend beyond end 26. Button 12 has sufficient
thickness and diameter to retain necessary strength in spite
of cavity 32 and passage 30.
~ utton 12 is fastened with screw 34 to rod 14. Rod
14 is a plug of several inches in length and is inserted in
the end of tube 16 and attached with a plurality of randomly
located spot welds 36 Preferably, rod 14 extends a short
distance from the end of tuhe 16 so that tube 16 does not
interfere with receiver 18 when button 12 is placed in
receiver 18. Rod 14 provides for and strengthens the end of
tube 16 for the attachment of button 12 with screw 34.
Receiver 18 is formed to include a cradle 38 with a wa]l 40
on one side and a lip 42 on the other. Receiver 18 is pre-
ferably a cylindrical block with ends 44, 46. End 44 may be
trimmed at the corner to eliminate unnecessary mass. A suf-
ficient flat surface, however, must be retained to butt
.
against rod 20. Cradle 38 is formed to include a cavity
extendir.g inwardly from the cylindrical wall and ending in a
semi-cylindrical curvature coaxial with the axis of the
block. Lip 42 results when a slot centered on the cavity of
cradle 38 is formed. The slot end is semi-cylindrical, and
coaxia] with the axis of the block. The slot between the
sides of lip 42 has width sufficient to allow rod 14 to pass
therethrough. Button 12 has a diameter greater than the
- ~l2~5~
--8--
diameter of rod 14 so that lip 42 retains button 12 from
sliding axially from cradle 38. The width and cylindrical
diameter oE the cavity of cradle 38 is slightly greater than
the diameter of button 12 to allow button 12 to be easily
received by cradle 38, while yet maintaining a relatively
snug abutment. End A6 is preferably rounded with the inner
portion collapsing toward lip 42 so as to leave only a rela-
tively short thickness for lip 42. In this way, end 46 and
lip 42 do not interfere with tube 16 as rod 14 passes through
the slot ~ormed by lip 42.
An axial passage 48 extends through rear wall 40.
Additionally, a cavity 50 is coaxial with the axis of
receiver 18. As with passage 30 and cavity 32 of button 12,
passage 48 and cavity 50 of receiver 18 are sized to receive
screw 52. As with hutton 12, the thickness and diameter of
receiver 18 are sufficient to provide the strength charac-
teristics for a particular application. As indicated herein-
before, end 44 of receiver 18 butts against rod 20 and is
fastened thereto with screw 52. Rod 20 is a plug of several
inches in length and is attached to tube 22 with a plurality
of random spot welds 36 through openings in tube 22. As with
rod 14, rod 20 provides for and strengthens the end of tube
22 for the attachment of receiver 18 with screw 52.
A locking mechanlsm, such as clip 24, is located to
hold button 12 snugly in cradle 38. A number of equivalent
lockin~ mechanisms are possible, but a simple embodiment is
shown to include a passage 54 in wall 40 at the top of button
12. Clip~24 has a ].ower leg 56 which passes through passage
54, and an upper leg 58 which retains clip 24 to the upper
edge of wall 40.
Connector 10 may be used to interconnect a pair of
tubes 16, 22, as shown in FIGURE 2. Also, a plurality of
connectors 10 may be used in a similar fashion to connect a
pair of trusses together as shown in FIGURES 5 and 6.
Trusses 60, 62 in FIGURE 5 each have three tubes 16', 22'.
-
g ~L2~3~i7fl~)
Varlous wehbing rods are we]ded or otherwise attached to hold
the tubes in a fixed, spaced-apart structural relationship.
A button 12' is attached to the end of each tube 16' at a rod
14' in the fashion described hereinhefore. Similarly, a
receiver 18' is attached to the end of each tube 22' at a rod
20'. With such configuration, truss 62 is connected to truss
60 by simply sliding all of buttons 12' into receivers 18'
simultaneously. Appropriate lock mechanisms prevent the
trusses from inadvertently separating.
Trusses 66, 68 in FIGURE 6 are connected together in
a similar fashion. Trusses 66, 68 each have four tubes 16 " ,
22 " connected together with webbing 64''. Buttons 12l' and
receivers ]8'' are attached in the fashion described herein-
before. All of buttons 12'' are received simultaneously by
receivers 18'' to hold truss 66 to truss 68. A locking
mechanism for each of connectors 10 " prevents inadvertent
disconnection.
As shown in FIGURE 4, interconnect mechanism 10 may
also be used in a space frame structure designated herein as
70. Space frame 70 includes nodes 72, 74. A plurality of
tubes 76 extend between nodes 72, 74 and other nodes (not
shown) or other structural members (not shown). Each node,
for example 72, has a plurality of faces 78. Centered in
each face is a threaded passage 80. A receiver 18' " is
attached to the various faces 78 which are needed for use as
attachments. ~eceivers 18''' are attached with a screw 52'''
in the same fashion as screw 52 attaches a receiver 18 to a
rod 20. Tubes 76 have buttons 12 " ' attached at both ends in
order to be received at each node. Since a node may be
formed to have faces in a variety of directions and since a
tuhe may be connected to extend generally perpendicular to
any particular face, nodes and tubes may be used to create a
variety of designs in the usual fashion of space frames and,
consequently, may be used in any of the various applications
~L~d257
-10
appropriate for space frames. The present invention,
however, is particularly advantageous for space frame
creation since it is so rapidl~ assembled and disassembled,
whi]e yet maintaining structural integrity and strength.
In use, as indicated, the present interconnecting
mechanism is rapidly assembled. The buttons and receivers
are preattached to rods, tubes, trusses or similar structural
members. At an assembly site, assemblers simply insert the
buttons into the receivers so the buttons rest in the cradles
oE the receivers and are retained between the lips and end
walls of the cradles. The buttons are locked in place using,
for example, a clip 24 or some other locking mechanism~ In
the case of space frame assembly, receivers 18''' are
attached to appropriate faces 78 of nodes. Tubes 7fi with
buttons 12 "' at both ends are extended between a pair of
nodes and slipped in the receivers and locked in the same
fashion as hereinbefore indicated. Various structural
desi~ns may be assembled since the aces of the nodes face in
many directions and numerous structural tubes may be attached
to each node. Disassembly of the space frame or of other
structural connections using apparatus 10 is possible and
rapidly accomplished simply by removing or releasing the
locking device and slipping the structural members having
buttons ~rom the receivers of attàched structural members.
Thus, not only is diverse and rapid assembly facilitated, but
disasse~bly is easy and reuse of the structural members and
connecting devices is feasible and incredibly advantageous.
As an a]ternative to clip 24 for locking a button in
a receiver, FIGURES 7-10 show an alternate embodiment of the
connecting apparatus of the present invention which provides
for rotation of the receiver with respect to the member to
which it is attached. Referring to FIGURES 7 and 8, connec-
tor apparatus 10'''' is shown with a button 12'''' attached
to a pluq 14'l'' in the end of a tubular member 16'''' with a
i7'~
, .. ~
bolt 34 " ''. In this embodiment, button 12'''' is shown to
have a neck portion 90 having a smaller diameter than the
diameter of the outer portion 92 which is received in
receiver 18 " ''. Also, plug 14'''' extends somewhat beyond
the end of tubular member 16'''' with the extended portion 9~
having a diameter approximately equal to the outer diameter
of tubular member 16''''.
Receiver 18'''' is fastened to plug 20'''' with bolt
52''''. Plug 20'''' is formed similar to plug 14'''' to have
an extending portion 96 with a diameter approximatley the
same as the outer diameter of tubular member 22''''. Plug
20'''' is welded or otherwise attached to tubular member
22'''' as is plug 14'''' to tubular member 16 "''. Receiver
18 " '' is formed to include a cradle 38''`' in the fashion of
cradle 38 described hereinabove. The back wall 40'''' inclu-
des a cavity 50'''' and an axial passage 48'''' for receiving
the head 98 and shank 100 of bolt 52''l'. A metallic bushing
102 is located between head 98 and the back wall 104 of the
cavity which receives head 98. Another metallic bushing 106
is located between the facing suraces of receiver 18'''' and
plug 20''''. The metallic bushings 102 and 106 allow
receiver 18 "'' to be rotated without loosening bolt 52''''.
In this regard, bolt 52'''' is preferably held in place with
an appropriate adhesive material between its threads and the
threads of plug 20'''' or with other known locking mechanism.
A f;rst O-ring seal 108 may be formed in the f'acing surface
of either plug 20'''' or receiver 18''''. A second O-ring
seal 110 may be ~ormed in either the wall surface of cavity
50'''' or in the surface of head 98. Seals 108 and 110
enclose a space which includes bushings 102 and 106 so that a
]ubricant grease may be used in the space to make rotation of
receiver 18'''' easier.
A mechanism for preventing rotation of receiver
18'''' is provided so that undesirable or inadvertent rota-
-12-
tion is not possible. The preventing mechanism 112 includes
a plunger 114 located along the centerline of cradle 38 " ''
in the outer wall 118 of receiver 18'''' in the space between
cavity 38'''' and plug 20 " 'l. A passage 116 is formed in
outer wall 118 having a smaller diameter near the outer wall
118 and a larger diameter portion 120 near the cavity 50 " "
for head 98 of bolt 52''''. Plunger 114 is formed to have
larger diamter knobs 120 and 122 with a neck 124 therebet-
ween. A coil spring 126 is located between wall 128 at the
10 end of the larger diameter passage ~118 and knob 122 of
p]unger 114 which is fitted in portion 118. Thus, plunger
114 is biased so that knob 122 is forced against head 98 of
bolt 52 "''.
Head 98 includes at least one cavity 130 in its
15 cylindrical surface for receiving knob 122 of plunger 114 and
thereby preventiny further rotation of receiver 18'''' with
respect to structural membar 22''''. It is often desirable
to include a plurality of equally spaced cavities 130 about
head 98.
2n The present interconnecting apparatus may be used
without the necessity of other tools to aid in connecting one
structural member to another. In this regard, it is pre-
ferable to form the outer cylindrical surface 132 of receiver
18'''' with grooves or knurls so that it may be easily
graspe~ and turned. It is also preferable to have a mecha-
nism such as cam 134 in operable attachment to plunger 114 so
that plunger 114 may be easily functioned without the need of
a pliers or other tool. Cam 134 has an arcuate portion 136
near wall 118 and a straight portion 138 extending away
therefrom. Cam 134 i-s pivotally attached to knob 120 of
plunger 114 at pivot pin 140. Thus, when plunger 114 moves
into a cavity 130, straight portion 138 of cam 134 forms a
slight incline with wall 118. To retract plunger 114 from
cavity 130, straight portion 138 is pivoted about pin 140 to
. . ~. . .
. .
-13- ~
force arcuate portion 136 against wall 11~ and move plunger
114 radially outwardly.
In use, and in reference to connecting first and
second trusses 60'''' and 62'''' together, reference is made
to FIGURES 9 and 10. A]l receivers attached to first truss
60'''' are oriented so that the cradles open in the same
direction and the centerlines of the cradles are generally
parallel to one another. In this fashion, the buttons 12''''
of second truss 62'''' are easily slipped into all cradles
simultaneously. Trusses 60'''' and 62'''' are locked
together by rotating each receiver until further rotation is
prevented by a functioning of plunger 114. Preferably, each
receiver is rotated so that the cradles open outwardly from
the centerline of truss 60 " " and the centerlines of the
various cradles come close to intersecting near the cen-
terli~e of truss 60 "''. It is understood, of course, that
exactness is not re~uired with respect to the intersection of
the various cradle centerlines, but the closer such intersec-
tion comes to the centerline of truss 60'''', the more unli-
kely an inadvertent rotation of one or more of receivers18'''' would occur and an inadvertent disconnection take
place. Disconnection of trusses 60 " '' and 62'''' is
accomplished by levering the plungers 114 out of cavities 130
with cams 134 and rotating the receivers so the cradles again
open in the same direction and the cradle centerlines are
generally parallel. Truss 60'''' is then lifted from truss
62'''' thereby moving buttons 12 " '' from receivers 18'l''.
The description hereinbefore has been directed to a
preferred and alternate embodiment having several applica-
tions. It is understood, however, that the structural mem-
bers, rods, buttons and receivers need not be cylindrical in
shape. It is only necessary that various parts mate in the
sense of the embodiments described. In like fashion, it is
understood that the tubes, trusses and space frame applica-
~z~
-14-
tions presented are only representative of the numerous
applications possible with the present invention.
Consequently, although numerous advantages and details of
structure and unction have been set forth, they must be con-
sidered exemplary. Changes made, especially in matters ofshape, size, and arrangement, to the full extent extended by
the general meaninq of the terms in which the appended claims
are expressed are understood to be within the principle of
the present invention.
