Tubing connector

A tubing connector enables an attachment tube to be selectively and removably connected to the side of a base tube. A tubular support member is affixed to the base tube and projects therefrom. A clip is mounted to one wall of the support member, and has an aperture therethrough which is threaded to receive a set screw. A slot in the wall of the support member allows the set screw to pass therethrough. The set screw is of a length which will extend across the interior of the support member so as to contact the opposite wall when rotated in a clockwise fashion. The attachment tube is connected to the support member by sliding the attachment tube thereover. The attachment tube has an aperture aligned with the set screw to allow access thereto. Clockwise rotation of the set screw will expand the support member by pushing outwardly on the wall with the clip on it and the wall opposing the clip, thereby causing frictional contact with the attachment tube. A second embodiment of the invention utilizes a support tube which has a threaded aperture in place of the removable clip of the first embodiment. Rotation of the set screw forces the opposite walls of the support member apart so as to cause frictional contact with the interior of the attachment tube and firmly hold it in place.

TECHNICAL FIELD 
The present invention relates generally to a connector for attaching 
sections of tubing to one another. 
BACKGROUND OF THE INVENTION 
In the fabrication of store fixtures and support structures for other uses, 
it is common to utilize sections of modular tubing which are removably 
connected together. In forming a "T" connection, wherein the end of one 
elongated tube is mounted perpendicularly to the side of a second 
elongated tube, it is common to affix a tubular peg or the like to the 
side of the tube over which the hollow end of the second tube is then 
removably mounted. The problem with such a method is that the peg is 
welded to the tube along its outside edges, discoloring the tube and 
permitting easy observation of unsightly welds. 
A second problem with previous connection methods was in the use of a set 
screw or the like threaded through an aperture in the attachment tube so 
as to abut the connector peg on the base tube. Because the tube was of a 
material which was relatively thin, there were few threads capable of 
supporting the set screw. Thus, the aperture threads could easily be 
stripped upon overtightening of the set screw. 
Another problem lies in the use of set screws is in the fact that set 
screws. Set screws can be easily lost when backed out of the threaded 
aperture. In order to remove the attachment tube from the peg of prior art 
connectors, it was necessary to back the set screw outwardly nearly 
completely from the tube. Keeping track of small parts such as set screw 
and the like is time consuming and can result in the needless loss of time 
in attempting to assemble a tubing support frame. 
It is therefore a general object of the present invention to provide an 
improved tubing connector. 
Another object of the present invention is to provide a tubing connector 
which is mountable to the side of a tube without requiring an outside 
observable weld. 
A further object is to provide a tubing connector which will more securely 
hold the attachment tube in combination with the base tube, than prior art 
connectors. 
Another object of the present invention is to provide a tubing connector of 
a type with a set screw which cannot be backed out of the attachment tube. 
Yet another object of the present invention is to provide a tubing 
connector which is simple to manufacture and easy to install and use. 
These and other objects of the present invention will be apparent to those 
skilled in the art. 
SUMMARY OF THE INVENTION 
The tubing connector of the present invention enables an attachment tube to 
be selectively and removably connected to the side of a base tube. A 
tubular support member is affixed to the base tube and projects therefrom. 
An opening in the base of the support member allows the support member to 
be welded to the base tube on the interior edge, so as to leave a "clean" 
edge along the exterior of the support member. A clip is mounted to one 
wall of the support member, and has an aperture therethrough which is 
threaded to receive a set screw. A slot in the wall of the support member 
allows the set screw to pass therethrough. The set screw is preferably of 
a length which will extend across the interior of the support member so as 
to contact the opposite wall when rotated in a clockwise fashion. In this 
way, clockwise rotation will expand the support member by pushing 
outwardly on the wall with the clip on it and the wall opposing the clip. 
The attachment tube is connected to the support member by sliding the 
attachment tube thereover. The attachment tube has an aperture slightly 
smaller than the diameter of the set screw, and aligned therewith, such 
that a hex wrench or the like may be inserted through the aperture in the 
attachment tube to rotate the set screw. In this fashion, expansion of the 
support member will cause frictional contact with the attachment tube to 
firmly hold the attachment tube in place. 
A second embodiment of the invention is designed for use with an attachment 
tube which has a length greater than its width. In such a case, the 
support member of the first embodiment is still utilized, but is located 
adjacent a filler member. A slightly longer set screw is utilized, and an 
aperture is formed in the rearward wall of the support member such that 
the set screw will pass completely through the support member and project 
against one wall of the filler member. Once the attachment tube is placed 
over the support member and filler member, the set screw may be rotated so 
as to force the filler member away from the support member, thereby 
causing frictional contact against opposite interior walls of the 
attachment tube to firmly hold it in place. 
A third embodiment of the invention utilizes a support tube which has a 
threaded aperture in place of the removable clip of the first embodiment. 
Rotation of the set screw again forces the opposite walls of the support 
member apart so as to cause frictional contact with the interior of the 
attachment tube and firmly hold it in place.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, in which identical or corresponding parts 
are identified by the same reference numeral, and more particularly to 
FIG. 1, the tubing connector of the present invention is designated 
generally at 10 and includes a support member 12 and a removable clip 14. 
For purposes of description, a first elongated tube 16 will be identified 
as the "base" tube, and will serve as the tube upon which a second 
"attachment tube" 18 will be connected. Base tube 16 is preferably 
rectangular and includes an upper longitudinal side 20 upon which one end 
of attachment tube 18 will be connected. Although this description will 
show attachment tube 18 connected to base tube 16 in a perpendicular 
fashion, it should be understood that various angles of connection between 
the tubes 18 and 16 are also possible utilizing the present invention. 
Support member 12 is a generally rectangular upstanding hollow tubular 
member having a forward face 22, opposing rearward face 24 and a pair of 
opposite sides 26 and 28. For purposes of description, support member 12 
will be designated as having a lower end 12a and upper end 12b. The lower 
end of front face 22 has an aperture 30 therein which allows access to the 
interior of support member 12. Aperture 30 allows support member 12 to 
have weld 32 applied along the interior thereof. Thus, a "clean" 
connection between connector 10 and base tube 16 is possible along the 
outside edges of support member 12. 
Front face 22 of support member 12 has an indented surface 34 extending to 
the upper end 12b, as shown in the drawings. Indented surface 34 is 
indented a distance such that attachment of clip 14 thereto will form a 
generally flush surface along face 22. An aperture 36 in indented surface 
34 will receive a set screw 38 mounted on clip 14, as described in more 
detail hereinbelow. 
Referring now to FIGS. 2 and 3, clip 14 includes a bracket 40 bent to form 
a forward leg 42 and rearward leg 44 with a bend 46 therebetween holding 
legs 42 and 44 in parallel relationship. Rearward leg 44 has a threaded 
aperture 48 generally centered therethrough which will threadably receive 
set screw 38 therethrough. Forward leg 42 has an aperture 50 therethrough 
larger than, and axial to, aperture 48, such that set screw 38 may be 
inserted therethrough. A nut 52 is held in position over aperture 48 by a 
pair of rigid lips 54 as shown in the drawings. Lips 54 will retain nut 52 
in position so that it will not rotate or be pushed outwardly away from 
rearward leg 44 as set screw 38 is threaded therethrough. 
A small arcuate lip 56 is formed to project inwardly from forward leg 42 so 
as to be retained by the upper edge of aperture 36 once clip 14 is placed 
in position on forward face 22 of support member 12. Forward leg 42 of 
bracket 40 has a thickness substantially equal to the depth of the 
indentation of indented surface 34 on front face 22, so as to form a flush 
surface when clip 14 is installed on indented surface 34 (see FIG. 3), so 
that attachment tube 18 will slide easily over support member 12. 
An aperture 58 is formed in attachment tube 18 which will be aligned with 
apertures 48 and 50 so as to allow insertion of a wrench 59 to rotate set 
screw 38. The diameter of aperture 58 is preferably smaller than the 
exterior diameter of the head of set screw 38, such that counterclockwise 
rotation of set screw 38 will abut the head of the set screw against the 
interior surface of attachment tube 18, as shown in FIG. 5, for a purpose 
described below. 
The tubing connector 10 of the present invention is utilized in situations 
where an attachment tube 18 is to be extended outwardly from a base tube 
16. The support member 12 is first affixed in the appropriate position on 
base tube 16 by welding or the like. A clip 14 is then slipped over 
indented surface 34 such that lip 56 on leg 42 is received in aperture 36 
to hold the clip in place. Attachment tube 18 is then slid over connector 
10 (see FIG. 3) like a sleeve until aperture 58 is aligned with apertures 
48 and 50 and the head of set screw 38 is viewed in aperture 58. Clockwise 
rotation of set screw 38 by a hex wrench 59, screwdriver or the like, will 
cause the end of set screw 38 to press against the interior side of the 
rearward face 24 of support member 12. This will bias rearward face 24 and 
forward face 22 outwardly in opposite directions and thereby grip 
attachment tube 18 by outward enlargement of support member 12 (see FIG. 
4). Enlargement of the diameter of support member 12 firmly grips 
attachment tube 18. 
A less firm, temporary grip is possible by rotating set screw 38 in a 
counterclockwise direction such that the head of set screw 38 abuts 
against the interior face of attachment tube 18 (see FIG. 5). The small 
amount of force will maintain the position of attachment tube 18 until it 
is desired to fully tighten the connection by clockwise rotation of the 
set screw. 
Referring now to FIGS. 6 and 7, a second embodiment of the invention is 
utilized in situations where the attachment tube 18' has a cross-section 
twice as wide as its depth. While an elongated version of the first 
embodiment would work, it is preferred that the embodiment shown in FIGS. 
6 and 7 be utilized in such a situation. A support member 12' is utilized 
in combination with a second filler member 60 having approximately the 
same cross-sectional diameter. Support member 12' and filler member 60 are 
mounted to base tube 16 such that attachment tube 18' will fit thereover 
with close tolerance. An aperture 62 is formed in rear wall 24' of support 
member 12' such that set screw 38' will extend therethrough and against 
one wall of filler member 60. An aperture 30' in filler member 60 allows 
filler member 60 to be welded to base tube 16' along the interior lower 
edge, in a fashion similar to support member 12'. Attachment tube 18' has 
an aperture 58' located so as to access set screw 38' in a manner similar 
to that of aperture 58 in attachment tube 18. 
In a third embodiment of the invention, as shown in FIG. 8, the base tube 
16 and attachment tube 18 are identical to those of the first embodiment, 
the change being only in the support member 12". In this embodiment of the 
invention, support member 12" has a threaded aperture 62 in its forward 
wall 22". This eliminates the necessity for utilizing the removable clip 
14 of the first embodiment. Set screw 38" is threaded through aperture 62 
and will abut the rearward wall 24" when rotated in a clockwise direction. 
Attachment tube 18 has an aperture 58 identical to that of the first 
embodiment, with a diameter slightly less than the diameter of set screw 
38", such that the set screw cannot be backed out of the support member 
through aperture 58 in attachment tube 18. 
Whereas the invention has been shown and described in connection with the 
preferred embodiments thereof, it will be understood that many 
modifications, substitutions and additions may be made which are within 
the intended broad scope of the appended claims. For example, nut 52 may 
be permanently affixed to rearward leg 44 of bracket 40, so as to maintain 
the position of the nut thereon. Likewise, set screw 38 may have a 
hex-type head, or a slot for receiving a screwdriver, such that the set 
screw may be operated by insertion of the appropriate tool through the 
aperture in the attachment tube wall. 
It can therefore be seen that the tubing connector of the present invention 
fulfills at least all of the above-stated objectives.