GB2117856A - Tube joint - Google Patents

Abstract

A tube joint for joining tubes together end to end for radio aerials, fishing rods, etc. comprises a tapered end on one tube 1, the taper being indented at 4 and having slots 5. The tapered end fits into the hollow end of another tube 3 which has an inner rib 7. The rib rides up the taper and fits into the indentations 4, the slots 5 affording resilience. <IMAGE>

Description

SPECIFICATION Tube joint The invention relates to a joint for joining tubes end to end. Particular application for the invention is found in detachable multi-part rods or tubes such as for radio aerials, fishing rods, tent poles or the like.

In the past, such multi-part rods or tubes have been formed by push-fitting a reduced end of one tube into the open end of the next. Generally, the tubes are held together merely by friction.

However, it is also possible to incorporate coil springs within the tubes so that the springs tend to draw the tubes together. The object of the present invention is to provide an improved joint.

According to the invention there is provided a tube joint for joining two tubes end to end, the joint comprising a tapered end on one tube, which end fits into an end of another tube, the said other tube having one or more protrusions extending from its inner wall and the tapered end having one or more indentations, the protusions engaging in the indentations when the tubes are joined together, and one or both of the tubes having longitudinal slots, each slot being closed at both ends, whereby spring leaves are defined which can flex resiliently to allow the protrusion to ride over the taper and lodge in the indentations as the tubes are slid together.

By "longitudinal" is meant substantially parallel with the tube axis, although the slots may be skewed to some extent.

Although the protrusions and/or indentations may be discrete, thus providing rotational location as well as longitudinal location, it is preferred that the indentations are constituted by a continuous groove in the tapered end and the protrusions are constituted by a continuous rib within the end of the other tube. This rib may be made by deforming the tube by rolling a groove from the outside.

The slots should extend on both sides beyond the indentations or protrusions, because preferably that is the position where maximum deflection is obtained.

Preferably, there are no slots in the said other tube, slots being formed only in the tapered end of the said one tube. There are at least two slots and while there may be three, there are preferably four slots. The number and dimensions of the slots, the degree of taper and the size of the protrusions and indentations will depend upon the materials of which the tubes are made. The invention is applicable to tubes made of any suitable material, such as plastics. However, the principal application of the invention is found in metal tubes and in a preferred embodiment of the invention a radio aerial is made of such tubes which are made of berylluim-copper.

An embodiment of the invention will now be described with reference to the accompanying drawing, the sole figure of which is an elevation of a joint in accordance with the invention.

Referring to the drawing there is shown a first tube 1 which is swaged to form a tapered end 2 and this is to be joined to a second tube 3 which has an essentially cylindrical end.

A groove 4 which constitutes an indentation is rotled into the tapered end 2 and four slots 5 (of which only two are shown in the drawing) are cut.

Each slot is closed at both ends.

A groove 6 is rolled into tube 2 so as to provide a continuous rib 7 protruding from the inside wall of the tube.

The arrangement is such that when the tapered end 2 is inserted into tube 3, rib 7 engages with the taper as the tubes are pressed together this deforms the tapered end by pressing inwardly slightly the leaves defined by the slots 5. Because of the nature of the material these leaves constitute resilient springs and when the rib 7 is pushed far enough to engage groove 4 the leaves spring back so as to hold the tubes firmly together with the rib engaged in the groove.

Clearly, for a multi-part tube, each part will be formed at one end with a tapered end 2 and at the other with a receiving end such as is shown for tube 3 in the drawing.

The invention is not restricted to the details of the embodiment described above with reference to the drawing. For example, slots may be formed in the outer tube as well as, or instead of, the inner tube.

Claims

1. A tube joint for joining two tubes end to end, the joint comprising a tapered end on one tube, which end fits into an end of another tube, the said other tube having one or more protrusions extending from its inner wall and the tapered end having one or more indentations, the protrusions engaging in the indentations when the tubes are joined together, and one or both of the tubes having longitudinal slots, each slot being closed at both ends whereby spring leaves are defined which can flex resiliently to allow the protrusion to ride over the taper and lodge in the indentations as the tubes are slid together.

2. A tube joint as claimed in claim 1 wherein the indentations are constituted by a continuous groove in the tapered end and the protrusions are constituted by a continuous rib within the end of the other tube.

3. A tube joint as claimed in claim 2 wherein the rib is made by deforming the tube by rolling a groove from the outside.

4. A tube joint as claimed in any of the preceding claims wherein there are no slots in the said other tube, slots being formed only in the tapered end of the said one tube.

5. A tube joint as claimed in any of the preceding claims wherein there are four slots in the or each tube with slots.

6. A tube joint as claimed in any of the preceding claims embodied in a radio aerial

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Tube joint The invention relates to a joint for joining tubes end to end. Particular application for the invention is found in detachable multi-part rods or tubes such as for radio aerials, fishing rods, tent poles or the like. In the past, such multi-part rods or tubes have been formed by push-fitting a reduced end of one tube into the open end of the next. Generally, the tubes are held together merely by friction. However, it is also possible to incorporate coil springs within the tubes so that the springs tend to draw the tubes together. The object of the present invention is to provide an improved joint. According to the invention there is provided a tube joint for joining two tubes end to end, the joint comprising a tapered end on one tube, which end fits into an end of another tube, the said other tube having one or more protrusions extending from its inner wall and the tapered end having one or more indentations, the protusions engaging in the indentations when the tubes are joined together, and one or both of the tubes having longitudinal slots, each slot being closed at both ends, whereby spring leaves are defined which can flex resiliently to allow the protrusion to ride over the taper and lodge in the indentations as the tubes are slid together. By "longitudinal" is meant substantially parallel with the tube axis, although the slots may be skewed to some extent. Although the protrusions and/or indentations may be discrete, thus providing rotational location as well as longitudinal location, it is preferred that the indentations are constituted by a continuous groove in the tapered end and the protrusions are constituted by a continuous rib within the end of the other tube. This rib may be made by deforming the tube by rolling a groove from the outside. The slots should extend on both sides beyond the indentations or protrusions, because preferably that is the position where maximum deflection is obtained. Preferably, there are no slots in the said other tube, slots being formed only in the tapered end of the said one tube. There are at least two slots and while there may be three, there are preferably four slots. The number and dimensions of the slots, the degree of taper and the size of the protrusions and indentations will depend upon the materials of which the tubes are made. The invention is applicable to tubes made of any suitable material, such as plastics. However, the principal application of the invention is found in metal tubes and in a preferred embodiment of the invention a radio aerial is made of such tubes which are made of berylluim-copper. An embodiment of the invention will now be described with reference to the accompanying drawing, the sole figure of which is an elevation of a joint in accordance with the invention. Referring to the drawing there is shown a first tube 1 which is swaged to form a tapered end 2 and this is to be joined to a second tube 3 which has an essentially cylindrical end. A groove 4 which constitutes an indentation is rotled into the tapered end 2 and four slots 5 (of which only two are shown in the drawing) are cut. Each slot is closed at both ends. A groove 6 is rolled into tube 2 so as to provide a continuous rib 7 protruding from the inside wall of the tube. The arrangement is such that when the tapered end 2 is inserted into tube 3, rib 7 engages with the taper as the tubes are pressed together this deforms the tapered end by pressing inwardly slightly the leaves defined by the slots 5. Because of the nature of the material these leaves constitute resilient springs and when the rib 7 is pushed far enough to engage groove 4 the leaves spring back so as to hold the tubes firmly together with the rib engaged in the groove. Clearly, for a multi-part tube, each part will be formed at one end with a tapered end 2 and at the other with a receiving end such as is shown for tube 3 in the drawing. The invention is not restricted to the details of the embodiment described above with reference to the drawing. For example, slots may be formed in the outer tube as well as, or instead of, the inner tube. Claims

1. A tube joint for joining two tubes end to end, the joint comprising a tapered end on one tube, which end fits into an end of another tube, the said other tube having one or more protrusions extending from its inner wall and the tapered end having one or more indentations, the protrusions engaging in the indentations when the tubes are joined together, and one or both of the tubes having longitudinal slots, each slot being closed at both ends whereby spring leaves are defined which can flex resiliently to allow the protrusion to ride over the taper and lodge in the indentations as the tubes are slid together.

2. A tube joint as claimed in claim 1 wherein the indentations are constituted by a continuous groove in the tapered end and the protrusions are constituted by a continuous rib within the end of the other tube.

3. A tube joint as claimed in claim 2 wherein the rib is made by deforming the tube by rolling a groove from the outside.

4. A tube joint as claimed in any of the preceding claims wherein there are no slots in the said other tube, slots being formed only in the tapered end of the said one tube.

5. A tube joint as claimed in any of the preceding claims wherein there are four slots in the or each tube with slots.

6. A tube joint as claimed in any of the preceding claims embodied in a radio aerial comprising a plurality of tubes of berrylluimcopper joined end to end.

7. A tube joint substantially as hereinbefore described with reference to the accompanying drawings.