EP1679106A1

EP1679106A1 - Elbow joint for tubes

Info

Publication number: EP1679106A1
Application number: EP05250086A
Authority: EP
Inventors: James Chun Chung Lim
Original assignee: COG Ltd
Current assignee: COG Ltd
Priority date: 2005-01-10
Filing date: 2005-01-10
Publication date: 2006-07-12

Abstract

An elbow joint has a first component including a first tube retainer for retaining an end portion of a first tube, a first connector formed integrally with the first tube retainer, a first pivot axis, and a first resistance surface at least partially surrounding the first pivot axis. The elbow joint also has a second component including a second tube retainer for retaining an end portion of a second tube, a second connector formed integrally with the second tube retainer, a second pivot axis co-linear with the first pivot axis, a second resistance surface at least partially surrounding the second pivot axis and engaging the first resistance surface with force sufficient to retain a selected angular disposition between the first and second components unless the force is exceeded.

Description

Background of the Invention

The present invention relates to elbow joints for connecting hollow tubes. More particularly, although not exclusively, the invention relates to reconfigurable elbow joints for use by children in assembling structures in which cardboard tubes are connected end-to-end with the elbow joints.

Objects of the Invention

It is an object of the present invention to provide an elbow joint comprising a pair of components that are pivotally interconnected, and to each of which a hollow tube can extend, and in which the angle between the hollow tubes can be readjusted and set.

Disclosure of the invention

There is disclosed herein an elbow joint, comprising:

a first component including a first tube retainer for retaining an end portion of a first tube, a first connector formed integrally with the first tube retainer, a first pivot axis, and a first resistance surface at least partially surrounding the first pivot axis, and
a second component including a second tube retainer for retaining an end portion of a second tube, a second connector formed integrally with the second tube retainer, a second pivot axis co-linear with the first pivot axis, a second resistance surface at least partially surrounding the second pivot axis and engaging the first resistance surface with force sufficient to retain a selected angular disposition between the first and second components unless the force is exceeded.

Preferably, the second connector is resiliently deformable and the first connector comprises an opening into which the second connector snap-engages.
Preferably, the first resistance surface comprises an inwardly facing circular array of teeth and the second resistance surface comprises an outwardly facing circular array of teeth.
Preferably, the second resistance surface comprises a plurality of slots enabling the outwardly facing array of teeth to resiliently deform to enable rotation of the first component with respect to the second component.
Preferably, the first and second tube retainers each comprise an annular protrusion having a plurality of lengthwise slots enabling portions of the protrusion flanked by the slots to deflect inwardly upon insertion into a tube.
Preferably, the annular protrusion comprises an annular flange through which the slots extend.
Preferably, the annular protrusion comprises a plurality of lugs aligned with each slot and extending radially of the protrusion for bearing against an inside surface of a tube.

Brief Description of the Drawings

A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic perspective illustration of an elbow joint,
Fig. 2 is a schematic front elevation of the elbow joint,
Fig. 3 is a schematic rear elevation of the elbow joint,
Fig. 4 is a schematic plan of the elbow joint,
Fig. 5 is a schematic parts-exploded plan view of the elbow joint,
Fig. 6 is a schematic end view of the elbow joint,
Fig. 7 is a schematic parts-exploded perspective illustration of the elbow joint,
Fig. 8 is another schematic parts-exploded perspective illustration of the elbow joint,
Fig. 9 is a schematic perspective illustration of an animal formed of tubes interconnected by a number of elbow joints of the preceding figures, and
Fig. 10 is a schematic perspective illustration of a structure formed of tubes interconnected by a number of elbow joints of Figs. 1 to 8.

Description of the Preferred Embodiment

In Figs. 1 to 8 of the accompanying drawings there is depicted schematically an elbow joint 10 comprising a first component 11 pivotally interconnected to a second component 12. Components 11 and 12 are formed of moulded plastics material.
The first component 11 comprises a first tube retainer 13 being substantially hollow cylindrical in form and comprising a number of lengthwise slots 21. There is an annular flange 22 at the distal end of the tube retainer and the slots 21 extend across the flange as shown. At the proximal end of each slot 21, there is provided a lug 23 that extends from the tube retainer to approximately the same radial extend as does the flange 22. The slots 21 enable the tube retainer 13 to compress radially as it is inserted into the end of a tube and the lugs 23 then bear against the inside surface of the tube end to cooperate with the flange 22 to maintain a proper alignment of the tube with respect to the first component 11. The shape of the flange makes it easier to insert the tube retainer into a tube end than it is to remove. There is a flange 22 just behind each lug to define the limit to which the tube retainer 13 can be inserted into a tube. The second component 12 includes an identical (second) tube retainer 14.
The first component 11 includes a first connector in the form of a cylindrical opening having an inwardly extending lip 16. Extending about the opening is a circular array of longitudinally extending, inwardly facing teeth 18 forming a first resistance surface.
The second component 12 has a second cylindrical connector 17 having a pair of diametrically opposed longitudinal slots 24 and a pair of semicircular outwardly facing barbs (not shown). The second connector 17 can thereby be snapped behind the lip 16 of the first connector and the barb is retained behind the lip to retain the components in pivotal association with one another.
surrounding the second connector 17 is a second resistance surface 19 in the form of a circular array of outwardly facing, longitudinally extending teeth. There are longitudinal slots 20 spaced periodically around the second resistance surface to provide the resistance surface with some flexibility and resilience. The teeth of the second resistance surface engage the teeth of the first resistance surface when the first and second components are connected. When so connected, the co-linear pivot axes of each component 11, 12 as represented at A in Fig. 3 defines a singular axis about which the mutual angular disposition of the respective tube retainers can be adjusted. When adjusting that angle, a degree of bending force must be applied whereupon the teeth of the second resistance surface ride over the teeth of the first resistance surface while deflecting inwardly and resiliently returning while making a clicking sound.
Example structures are shown in Figs. 9 and 10. These include a number of elbow joints 10 and a number of cardboard tubes 15 of the type that might otherwise be discarded from finished paper towel rolls.
It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, one or both of the resistance surfaces might comprise a smooth band of rubber or other fictional material instead of integrally formed teeth.

Claims

An elbow joint, comprising:
a first component including a first tube retainer for retaining an end portion of a first tube, a first connector formed integrally with the first tube retainer, a first pivot axis, and a first resistance surface at least partially surrounding the first pivot axis, and

a second component including a second tube retainer for retaining an end portion of a second tube, a second connector formed integrally with the second tube retainer, a second pivot axis co-linear with the first pivot axis, a second resistance surface at least partially surrounding the second pivot axis and engaging the first resistance surface with force sufficient to retain a selected angular disposition between the first and second components unless the force is exceeded.
The elbow joint of Claim 1, wherein the second connector is resiliently deformable and the first connector comprises an opening into which the second connector snap-engages.
The elbow joint of Claim 1 or Claim 2, wherein the first resistance surface comprises an inwardly facing circular array of teeth and the second resistance surface comprises an outwardly facing circular array of teeth.
The elbow joint of Claim 3, wherein the second resistance surface comprises a plurality of slots enabling the outwardly facing array of teeth to resiliently deform to enable rotation of the first component with respect to the second component.
The elbow joint of any preceding Claim, wherein the first and second tube retainers each comprise an annular protrusion having a plurality of lengthwise slots enabling portions of the protrusion flanked by the slots to deflect inwardly upon insertion into a tube.
The elbow joint of Claim 5, wherein the annular protrusion comprises an annular flange through which the slots extend.
The elbow joint of Claim 5 or Claim 6, wherein the annular protrusion comprises a plurality of lugs aligned with each slot and extending radially of the protrusion for bearing against an inside surface of a tube.