Tethered swivel cap

A flexible tether arrangement is provided between a fluid container (10) and a cap (12) to permit free swiveling of the cap for enabling it to be screwed onto the container. A tether line (14) has one end (30) attached to the container and the other end (32') attached in a swivelable manner to the cap. The cap has a projecting boss (20) with a relatively small journal hole (28) drilled into its end and a relatively large assembly hole (26) drilled into its side so as to communicate with the assembly hole. The end of the tether line has a stop (32') thereon, made of a ball of fusion, which is positioned at the junction of the two holes. The stop is smaller than the assembly hole so that after it is formed on the free end of the tether when it projects out from the assembly hole, it can be pulled back into the assembly hole. The stop is larger than the journal hole so that after it is so pulled back, it can not be pulled out of the journal hole. The arrangement can be used to join various other associated parts.

BACKGROUND 
1. Field of Invention 
This invention relates to tethered objects which can swivel, particularly 
to a tethered cap for a fluid container, which cap can swivel or rotate 
freely. 
2. Description of Prior Art 
In many applications there is a need to interconnect separate members so 
that they can swivel freely. The most common application is a liquid 
container and its cap: the cap should be able to swivel freely so that it 
can be screwed onto its container, yet should be held by a flexible tether 
so that it cannot be lost or misplaced. Another application is found in 
multi-part toys or disconnectable industrial or military assemblies which 
must be held together by a tether (so that they will not be lost) which 
should not be twistable (so that it will not tangle or wear). 
Heretofore many different arrangements were used to interconnect separate 
members so that they could swivel freely. The following is a discussion of 
these arrangements and their drawbacks: 
One type involved captivated cords which connected one object, such as a 
container cap to another, such as a container. Alexander U.S. Pat. No. 
79,536, 1868, is examplary. However in these arrangements the cord was 
fixed in a non-swivelable manner at each of its ends so that the cap could 
swivel only to a limited extent, in accordance with the flexibility or 
twistability of the cord. This is undesirable since twisting the cord 
tended to wear it out prematurely and also caused it to kink and knot. 
Also it is desirable to have a tether which is infinitely swivelable 
(i.e., one where the cap can be rotated an infinite number of times) so 
that the tether can be made shorter and so that the tether does not have 
to be pretwisted before screwing on the cap. (If a non-swivelable tether 
is not pretwisted, it will become awkwardly twisted after the cap is 
screwed on.) 
Another arrangement, shown in Klee U.S. Pat. No. 8,034, 1878, comprised a 
flexible tether which was passed through a horizontal hole in the cap 
and/or the container and was captivated by an enlarged stop at either or 
both of its ends. This type of tether was disadvantageous because a cap 
usually has to be twisted on a vertical axis to be screwed on; thus the 
horizontal hole(s) did not permit the right type of swiveling. Also the 
enlarged stop was not held in place and thus tended to extend out from the 
cap or container where it interfered with usage of the container. 
In still another type, shown in Doyle U.S. Pat. No. 281,719, 1879, the cap 
had awkward top and side holes with tethers. The holes did not communicate 
and were difficult to use. 
Boynton/Fravel U.S. Pat. No. 602,822, 1898, shows a stopper held by 
captivated rings and beads which were snapped into an elastic matrix. This 
of course did not permit swiveling and the snap-in beads were not 
reliable. 
Copper U.S. Pat. No. 1,611,852, 1926, and Clemens U.S. Pat. No. 2,263,798, 
1941, show beaded wires with the end beads snapped into position. While 
permitting infinite swiveling, the snap-in captivation of the beads was 
unreliable and relatively expensive. 
Johnson U.S. Pat. Nos. 2,322,805 and 2,468,758, 1943 and 1949 employed a 
linked or flexible tether with an end stop which was captivated by passing 
it through a hole in a bar and welding the bar in place. While permitting 
infinite swiveling, this method was expensive and was not suitable for 
plastic parts. 
Italian Pat. No. 498,610, 1954 and Berry U.S. Pat. No. 2,854,789, 1958, 
show a cap or other tethered part with a through hole where a flexible 
tether extended through the hole; the tether had an end stop on the inside 
of the cap, inside the container, or on the distal side of the tethered 
part. Since this type of captivation allowed the hole to communicate with 
the interior of the container, it could not provide a watertight seal. 
Katzman/Gordon U.S. Pat. No. 3,874,570, 1975, shows a tether with an 
enlarged end which was inserted into a side, partial circumferential, 
groove in a cap. This type of tether did not permit infinite swiveling and 
was unreliable. 
Sherman/Francis U.S. Pat. No. 4,432,120, 1984, employed a bead chain or 
other flexible tether where end stops were captivated in laminated 
mounting ends which were attached to the cap and contained, respectively. 
This arrangement was difficult and expensive to fabricate and assemble and 
was unreliable in operation. 
OBJECTS AND ADVANTAGES 
Accordingly, several objects and advantages of the invention are to provide 
a tether arrangement for interconnecting two members in an infinitely 
swivelable manner. The tether arrangement is economical, reliable, easy to 
fabricate, and highly durable. Moreover it can be used with plastic or 
metal parts and does not extend out and will not otherwise interfere with 
free usage of the interconnected parts. The arrangement will not 
compromise a watertight seal when it is used to hold a cap for liquid 
containers. Further objects and advantages will become apparent from a 
consideration of the ensuing description and accompanying drawings.

DETAILED DESCRIPTION 
FIG. 1 shows a plan view of a flexible water container 10 with a screw-on 
cap 12 (with female threads) held by a flexible tether 14 in accordance 
with the invention. Container 12 has carrying straps, a replaceable liner 
(not shown) and related hardware, including a threaded male spout 16 which 
mates with cap 12. 
FIG. 2 is an enlarged view of the cap as shown in FIG. 1 and FIG. 3 is an 
enlarged view of the cap of FIG. 2 from a viewing angle normal to that of 
FIG. 2. The cap is molded of a plastic, such as nylon or polycarbonate, 
and has a base portion 18 and a top portion 20 which is integrally joined 
to base portion 18. Base portion 18 is similar to that of a conventional 
cap: it has internal (female) threads 22 which mate with the external 
(male) threads of spout 16 and vertical external ribs 24 for enabling it 
to be turned easily. 
In accordance with the invention, the cap has a top portion 20 which 
captivates tether 14, yet permits the cap to swivel in an infinite manner 
on tether 14. Top portion 20 has approximately the same height as base 18, 
but has a diameter about one-half that of base 18. It is initially formed 
to be "solid", i.e., voidless and homogeneous. Thereafter a relatively 
large-diameter horizontal assembly hole 26 is drilled partially through 
the top, i.e., about 2/3 across. Then a relatively small-diameter vertical 
journal hole 28 is drilled from the flat end of the top (the bottom 
surface as shown in the Figs.) to communicate with assembly hole 26. 
Alternatively assembly hole 26 can be a through hole, i.e., it can be 
drilled completely through the top. Also, alternatively, holes 26 and 28 
can be formed by the molding process as the top is made. 
The approximate dimensions and material of cap 12 in one commercial 
embodiment were as follows: diameter of base 18: 15.5 mm, diameter of top 
20: 8.4 mm, height of base: 9.1 mm, height of top 20: 5.6 mm, diameter of 
assembly hole 26: 3.2 mm, diameter of journal hole 28: 1.2 mm, spout 16: 
12.7 mm OD with #18 threads, material: Celcon.RTM. acetal resin, mfgd. by 
Celanese, colored black. 
Flexible tether 14 preferably is made of a thermosettable material, such as 
a braided nylon line, 1.1 mm in diameter and 15 cm long before 
installation. It is installed as follows: The proximal end of the tether 
is affixed to container 10 in any conventional manner, e.g., by passing it 
through a hole in a neck ring of the container and knotting the 
passed-through end, as indicated at 30 in FIG. 1. 
The distal end of tether 14 is then inserted into journal hole 28, bent, 
and pushed out through assembly hole 26, as indicated at 14' in FIG. 3. 
Then, to captivate the tether, its free end 32 is heated, e.g., by brief 
application of a flame or a hot tool, e.g., a soldering iron, until end 32 
forms an enlarged ball of fusion, as indicated at 32'. Ball 32' is formed 
to have a dimension which is larger than journal hole 28 and smaller than 
assembly hole 26 so that it can pass through hole 26, but not through hole 
28. In the exemplary case, ball 32' had a diameter of about 2.2 mm. 
Then the tether is pulled back to straighten it so that ball 32' will go 
into assembly hole 26, but will be stopped by journal hole 28, as 
indicated in FIG. 2. Thereupon ball 32' will be positioned at the junction 
of holes 26 and 28. 
OPERATION 
Operation and use of the tether arrangement of the invention is simple and 
straightforward. When cap 12 is not screwed onto spout 16, it is held by 
tether 14, yet can rotate freely and infinitely in journal hole 28. This 
is because, as best seen in FIG. 2, tether 14 forms a pivot pin or swivel 
and hole 28 forms a mating journal or guideway to enable cap 12 to rotate 
freely and infinitely, on a vertical axis when seen in FIG. 2. The cap can 
be screwed freely onto spout 16 as if it were not tethered due to its 
extreme freedom of rotatability on an axis which can be made coaxial with 
spout 16. The tether will be firmly and permanently attached to cap 12 
since ball 32' cannot be pulled out of relatively narrow journal hole 28. 
Also ball 32', and hence the tether line, will not readily come back out 
of assembly hole 26 since it would have to be bent to extend out of hole 
26, a relatively difficult operation in the partially-enclosed space where 
it is positioned. 
SUMMARY, RAMIFICATIONS, AND SCOPE 
Accordingly it is seen that, according to the invention, a tether 
arrangement is provided which can interconnect two members in an 
infinitely swivelable manner, yet in an economical, reliable, easy to 
fabricate, and highly durable manner. As stated, it can be used with 
plastic or metal parts, it does not extend out and will not otherwise 
interfere with free usage of the interconnected parts, and it will not 
compromise a watertight seal when it is used to hold a cap for liquid 
containers. 
While the above description contains many specificities, these should not 
be construed as limitations on the scope of the invention, but as 
exemplifications of the presently-preferred embodiments thereof. Many 
other ramifications and variations are possible within the teachings of 
the invention. For example, the tether arrangement can be used to connect 
any line with a free end to any member and to interconnect military 
components, toy components, etc. Instead of providing an end stop using a 
ball of fusion and a plastic tether, a clamped-on ball stop or other 
mechanical stop can be used. The tether line can thus be made of wire, 
chain, etc. The assembly and journal holes can have non-round 
cross-sectional shapes, as can the projecting portion (20) and the base 
portion (18) itself. Thus the scope of the invention should be determined 
by the appended claims and their legal equivalents, and not by the 
examples given.